1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 menu "Kernel hacking" 2 menu "Kernel hacking"
3 3
4 menu "printk and dmesg options" 4 menu "printk and dmesg options"
5 5
6 config PRINTK_TIME 6 config PRINTK_TIME
7 bool "Show timing information on print 7 bool "Show timing information on printks"
8 depends on PRINTK 8 depends on PRINTK
9 help 9 help
10 Selecting this option causes time st 10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output o 11 messages to be added to the output of the syslog() system
12 call and at the console. 12 call and at the console.
13 13
14 The timestamp is always recorded int 14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifi 15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp 16 be included, not that the timestamp is recorded.
17 17
18 The behavior is also controlled by t 18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documen 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20 20
21 config PRINTK_CALLER 21 config PRINTK_CALLER
22 bool "Show caller information on print 22 bool "Show caller information on printks"
23 depends on PRINTK 23 depends on PRINTK
24 help 24 help
25 Selecting this option causes printk( 25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "proces 26 in task context) or a caller "processor id" (if not in task context)
27 to every message. 27 to every message.
28 28
29 This option is intended for environm 29 This option is intended for environments where multiple threads
30 concurrently call printk() for many 30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where thes 31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple 32 line which was divided into multiple lines due to race) came from.
33 33
34 Since toggling after boot makes the 34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the k 35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface. 36 sysfs interface.
37 37
38 config STACKTRACE_BUILD_ID 38 config STACKTRACE_BUILD_ID
39 bool "Show build ID information in sta 39 bool "Show build ID information in stacktraces"
40 depends on PRINTK 40 depends on PRINTK
41 help 41 help
42 Selecting this option adds build ID 42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk 43 stacktraces printed with the printk format '%p[SR]b'.
44 44
45 This option is intended for distros 45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded giv 46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is 47 kernel module where the function is located.
48 48
49 config CONSOLE_LOGLEVEL_DEFAULT 49 config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)" 50 int "Default console loglevel (1-15)"
51 range 1 15 51 range 1 15
52 default "7" 52 default "7"
53 help 53 help
54 Default loglevel to determine what w 54 Default loglevel to determine what will be printed on the console.
55 55
56 Setting a default here is equivalent 56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> co 57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well. 58 value is specified here as well.
59 59
60 Note: This does not affect the log l 60 Note: This does not affect the log level of un-prefixed printk()
61 usage in the kernel. That is control 61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option. 62 option.
63 63
64 config CONSOLE_LOGLEVEL_QUIET 64 config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)" 65 int "quiet console loglevel (1-15)"
66 range 1 15 66 range 1 15
67 default "4" 67 default "4"
68 help 68 help
69 loglevel to use when "quiet" is pass 69 loglevel to use when "quiet" is passed on the kernel commandline.
70 70
71 When "quiet" is passed on the kernel 71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW pa 72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CON 73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74 74
75 config MESSAGE_LOGLEVEL_DEFAULT 75 config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)" 76 int "Default message log level (1-7)"
77 range 1 7 77 range 1 7
78 default "4" 78 default "4"
79 help 79 help
80 Default log level for printk stateme 80 Default log level for printk statements with no specified priority.
81 81
82 This was hard-coded to KERN_WARNING 82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely 83 that are auditing their logs closely may want to set it to a lower
84 priority. 84 priority.
85 85
86 Note: This does not affect what mess 86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use logl 87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL 88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89 89
90 config BOOT_PRINTK_DELAY 90 config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message b 91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && G 92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help 93 help
94 This build option allows you to read 94 This build option allows you to read kernel boot messages
95 by inserting a short delay after eac 95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the ker 96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N". 97 using "boot_delay=N".
98 98
99 It is likely that you would also nee 99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value. 100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj 101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before 102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adverse 103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the firs 104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOC 105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup condit 106 what it believes to be lockup conditions.
107 107
108 config DYNAMIC_DEBUG 108 config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support" 109 bool "Enable dynamic printk() support"
110 default n 110 default n
111 depends on PRINTK 111 depends on PRINTK
112 depends on (DEBUG_FS || PROC_FS) 112 depends on (DEBUG_FS || PROC_FS)
113 select DYNAMIC_DEBUG_CORE 113 select DYNAMIC_DEBUG_CORE
114 help 114 help
115 115
116 Compiles debug level messages into t 116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. T 117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various le 118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and 119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug( 120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by abo 121 enlarges the kernel text size by about 2%.
122 122
123 If a source file is compiled with DE 123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled b 124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note 125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* opt 126 turned on by many CONFIG_*DEBUG* options.
127 127
128 Usage: 128 Usage:
129 129
130 Dynamic debugging is controlled via 130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131 which is contained in the 'debugfs' 131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesyst 132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature. 133 making use of this feature.
134 We refer the control file as: <debug 134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug st 135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is: 136 format for each line of the file is:
137 137
138 filename:lineno [module]functi 138 filename:lineno [module]function flags format
139 139
140 filename : source file of the debug 140 filename : source file of the debug statement
141 lineno : line number of the debug st 141 lineno : line number of the debug statement
142 module : module that contains the de 142 module : module that contains the debug statement
143 function : function that contains th 143 function : function that contains the debug statement
144 flags : '=p' means the line is turne 144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the deb 145 format : the format used for the debug statement
146 146
147 From a live system: 147 From a live system:
148 148
149 nullarbor:~ # cat <debugfs>/dy 149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]func 150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx 151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc 152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_canc 153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154 154
155 Example usage: 155 Example usage:
156 156
157 // enable the message at line 157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file sv 158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 159 <debugfs>/dynamic_debug/control
160 160
161 // enable all the messages in 161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file sv 162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 163 <debugfs>/dynamic_debug/control
164 164
165 // enable all the messages in 165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module 166 nullarbor:~ # echo -n 'module nfsd +p' >
167 167 <debugfs>/dynamic_debug/control
168 168
169 // enable all 12 messages in t 169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func sv 170 nullarbor:~ # echo -n 'func svc_process +p' >
171 171 <debugfs>/dynamic_debug/control
172 172
173 // disable all 12 messages in 173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func sv 174 nullarbor:~ # echo -n 'func svc_process -p' >
175 175 <debugfs>/dynamic_debug/control
176 176
177 See Documentation/admin-guide/dynami 177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information. 178 information.
179 179
180 config DYNAMIC_DEBUG_CORE 180 config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic 181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK 182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS) 183 depends on (DEBUG_FS || PROC_FS)
184 help 184 help
185 Enable core functional support of dy 185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug t 186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for eac 187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where th 188 the case of embedded system where the kernel image size is
189 sensitive for people. 189 sensitive for people.
190 190
191 config SYMBOLIC_ERRNAME 191 config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in 192 bool "Support symbolic error names in printf"
193 default y if PRINTK 193 default y if PRINTK
194 help 194 help
195 If you say Y here, the kernel's prin 195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error name 196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kerne 197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel 198 (about 3KB), but can make the kernel logs easier to read.
199 199
200 config DEBUG_BUGVERBOSE 200 config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70 201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE 202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y 203 default y
204 help 204 help
205 Say Y here to make BUG() panics outp 205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP a 206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of 207 debugging but costs about 70-100K of memory.
208 208
209 endmenu # "printk and dmesg options" 209 endmenu # "printk and dmesg options"
210 210
211 config DEBUG_KERNEL 211 config DEBUG_KERNEL
212 bool "Kernel debugging" 212 bool "Kernel debugging"
213 help 213 help
214 Say Y here if you are developing dri 214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems. 215 identify kernel problems.
216 216
217 config DEBUG_MISC 217 config DEBUG_MISC
218 bool "Miscellaneous debug code" 218 bool "Miscellaneous debug code"
219 default DEBUG_KERNEL 219 default DEBUG_KERNEL
220 depends on DEBUG_KERNEL 220 depends on DEBUG_KERNEL
221 help 221 help
222 Say Y here if you need to enable mis 222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug optio 223 be under a more specific debug option but isn't.
224 224
225 menu "Compile-time checks and compiler options 225 menu "Compile-time checks and compiler options"
226 226
227 config DEBUG_INFO 227 config DEBUG_INFO
228 bool 228 bool
229 help 229 help
230 A kernel debug info option other tha 230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice be 231 in the "Debug information" choice below, indicating that debug
232 information will be generated for bu 232 information will be generated for build targets.
233 233
234 # Clang generates .uleb128 with label differen 234 # Clang generates .uleb128 with label differences for DWARF v5, a feature that
235 # older binutils ports do not support when uti 235 # older binutils ports do not support when utilizing RISC-V style linker
236 # relaxation: https://sourceware.org/bugzilla/ 236 # relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
237 config AS_HAS_NON_CONST_ULEB128 237 config AS_HAS_NON_CONST_ULEB128
238 def_bool $(as-instr,.uleb128 .Lexpr_en 238 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
239 239
240 choice 240 choice
241 prompt "Debug information" 241 prompt "Debug information"
242 depends on DEBUG_KERNEL 242 depends on DEBUG_KERNEL
243 help 243 help
244 Selecting something other than "None 244 Selecting something other than "None" results in a kernel image
245 that will include debugging info res 245 that will include debugging info resulting in a larger kernel image.
246 This adds debug symbols to the kerne 246 This adds debug symbols to the kernel and modules (gcc -g), and
247 is needed if you intend to use kerne 247 is needed if you intend to use kernel crashdump or binary object
248 tools like crash, kgdb, LKCD, gdb, e 248 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
249 249
250 Choose which version of DWARF debug 250 Choose which version of DWARF debug info to emit. If unsure,
251 select "Toolchain default". 251 select "Toolchain default".
252 252
253 config DEBUG_INFO_NONE 253 config DEBUG_INFO_NONE
254 bool "Disable debug information" 254 bool "Disable debug information"
255 help 255 help
256 Do not build the kernel with debuggi 256 Do not build the kernel with debugging information, which will
257 result in a faster and smaller build 257 result in a faster and smaller build.
258 258
259 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 259 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
260 bool "Rely on the toolchain's implicit 260 bool "Rely on the toolchain's implicit default DWARF version"
261 select DEBUG_INFO 261 select DEBUG_INFO
262 depends on !CC_IS_CLANG || AS_IS_LLVM 262 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
263 help 263 help
264 The implicit default version of DWAR 264 The implicit default version of DWARF debug info produced by a
265 toolchain changes over time. 265 toolchain changes over time.
266 266
267 This can break consumers of the debu 267 This can break consumers of the debug info that haven't upgraded to
268 support newer revisions, and prevent 268 support newer revisions, and prevent testing newer versions, but
269 those should be less common scenario 269 those should be less common scenarios.
270 270
271 config DEBUG_INFO_DWARF4 271 config DEBUG_INFO_DWARF4
272 bool "Generate DWARF Version 4 debugin 272 bool "Generate DWARF Version 4 debuginfo"
273 select DEBUG_INFO 273 select DEBUG_INFO
274 depends on !CC_IS_CLANG || AS_IS_LLVM 274 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
275 help 275 help
276 Generate DWARF v4 debug info. This r 276 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
277 if using clang without clang's integ 277 if using clang without clang's integrated assembler, and gdb 7.0+.
278 278
279 If you have consumers of DWARF debug 279 If you have consumers of DWARF debug info that are not ready for
280 newer revisions of DWARF, you may wi 280 newer revisions of DWARF, you may wish to choose this or have your
281 config select this. 281 config select this.
282 282
283 config DEBUG_INFO_DWARF5 283 config DEBUG_INFO_DWARF5
284 bool "Generate DWARF Version 5 debugin 284 bool "Generate DWARF Version 5 debuginfo"
285 select DEBUG_INFO 285 select DEBUG_INFO
286 depends on !ARCH_HAS_BROKEN_DWARF5 286 depends on !ARCH_HAS_BROKEN_DWARF5
287 depends on !CC_IS_CLANG || AS_IS_LLVM 287 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
288 help 288 help
289 Generate DWARF v5 debug info. Requir 289 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
290 5.0+ accepts the -gdwarf-5 flag but 290 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
291 draft features until 7.0), and gdb 8 291 draft features until 7.0), and gdb 8.0+.
292 292
293 Changes to the structure of debug in 293 Changes to the structure of debug info in Version 5 allow for around
294 15-18% savings in resulting image an 294 15-18% savings in resulting image and debug info section sizes as
295 compared to DWARF Version 4. DWARF V 295 compared to DWARF Version 4. DWARF Version 5 standardizes previous
296 extensions such as accelerators for 296 extensions such as accelerators for symbol indexing and the format
297 for fission (.dwo/.dwp) files. Users 297 for fission (.dwo/.dwp) files. Users may not want to select this
298 config if they rely on tooling that 298 config if they rely on tooling that has not yet been updated to
299 support DWARF Version 5. 299 support DWARF Version 5.
300 300
301 endchoice # "Debug information" 301 endchoice # "Debug information"
302 302
303 if DEBUG_INFO 303 if DEBUG_INFO
304 304
305 config DEBUG_INFO_REDUCED 305 config DEBUG_INFO_REDUCED
306 bool "Reduce debugging information" 306 bool "Reduce debugging information"
307 help 307 help
308 If you say Y here gcc is instructed 308 If you say Y here gcc is instructed to generate less debugging
309 information for structure types. Thi 309 information for structure types. This means that tools that
310 need full debugging information (lik 310 need full debugging information (like kgdb or systemtap) won't
311 be happy. But if you merely need deb 311 be happy. But if you merely need debugging information to
312 resolve line numbers there is no los 312 resolve line numbers there is no loss. Advantage is that
313 build directory object sizes shrink 313 build directory object sizes shrink dramatically over a full
314 DEBUG_INFO build and compile times a 314 DEBUG_INFO build and compile times are reduced too.
315 Only works with newer gcc versions. 315 Only works with newer gcc versions.
316 316
317 choice 317 choice
318 prompt "Compressed Debug information" 318 prompt "Compressed Debug information"
319 help 319 help
320 Compress the resulting debug info. R 320 Compress the resulting debug info. Results in smaller debug info sections,
321 but requires that consumers are able 321 but requires that consumers are able to decompress the results.
322 322
323 If unsure, choose DEBUG_INFO_COMPRES 323 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
324 324
325 config DEBUG_INFO_COMPRESSED_NONE 325 config DEBUG_INFO_COMPRESSED_NONE
326 bool "Don't compress debug information 326 bool "Don't compress debug information"
327 help 327 help
328 Don't compress debug info sections. 328 Don't compress debug info sections.
329 329
330 config DEBUG_INFO_COMPRESSED_ZLIB 330 config DEBUG_INFO_COMPRESSED_ZLIB
331 bool "Compress debugging information w 331 bool "Compress debugging information with zlib"
332 depends on $(cc-option,-gz=zlib) 332 depends on $(cc-option,-gz=zlib)
333 depends on $(ld-option,--compress-debu 333 depends on $(ld-option,--compress-debug-sections=zlib)
334 help 334 help
335 Compress the debug information using 335 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
336 5.0+, binutils 2.26+, and zlib. 336 5.0+, binutils 2.26+, and zlib.
337 337
338 Users of dpkg-deb via scripts/packag 338 Users of dpkg-deb via scripts/package/builddeb may find an increase in
339 size of their debug .deb packages wi 339 size of their debug .deb packages with this config set, due to the
340 debug info being compressed with zli 340 debug info being compressed with zlib, then the object files being
341 recompressed with a different compre 341 recompressed with a different compression scheme. But this is still
342 preferable to setting $KDEB_COMPRESS 342 preferable to setting $KDEB_COMPRESS to "none" which would be even
343 larger. 343 larger.
344 344
345 config DEBUG_INFO_COMPRESSED_ZSTD 345 config DEBUG_INFO_COMPRESSED_ZSTD
346 bool "Compress debugging information w 346 bool "Compress debugging information with zstd"
347 depends on $(cc-option,-gz=zstd) 347 depends on $(cc-option,-gz=zstd)
348 depends on $(ld-option,--compress-debu 348 depends on $(ld-option,--compress-debug-sections=zstd)
349 help 349 help
350 Compress the debug information using 350 Compress the debug information using zstd. This may provide better
351 compression than zlib, for about the 351 compression than zlib, for about the same time costs, but requires newer
352 toolchain support. Requires GCC 13. 352 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353 zstd. 353 zstd.
354 354
355 endchoice # "Compressed Debug information" 355 endchoice # "Compressed Debug information"
356 356
357 config DEBUG_INFO_SPLIT 357 config DEBUG_INFO_SPLIT
358 bool "Produce split debuginfo in .dwo 358 bool "Produce split debuginfo in .dwo files"
359 depends on $(cc-option,-gsplit-dwarf) 359 depends on $(cc-option,-gsplit-dwarf)
360 # RISC-V linker relaxation + -gsplit-d 360 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
361 # prior to 12.x: 361 # prior to 12.x:
362 # https://github.com/llvm/llvm-project 362 # https://github.com/llvm/llvm-project/issues/56642
363 # https://gcc.gnu.org/bugzilla/show_bu 363 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
364 depends on !RISCV || GCC_VERSION >= 12 364 depends on !RISCV || GCC_VERSION >= 120000
365 help 365 help
366 Generate debug info into separate .d 366 Generate debug info into separate .dwo files. This significantly
367 reduces the build directory size for 367 reduces the build directory size for builds with DEBUG_INFO,
368 because it stores the information on 368 because it stores the information only once on disk in .dwo
369 files instead of multiple times in o 369 files instead of multiple times in object files and executables.
370 In addition the debug information is 370 In addition the debug information is also compressed.
371 371
372 Requires recent gcc (4.7+) and recen 372 Requires recent gcc (4.7+) and recent gdb/binutils.
373 Any tool that packages or reads debu 373 Any tool that packages or reads debug information would need
374 to know about the .dwo files and inc 374 to know about the .dwo files and include them.
375 Incompatible with older versions of 375 Incompatible with older versions of ccache.
376 376
377 config DEBUG_INFO_BTF 377 config DEBUG_INFO_BTF
378 bool "Generate BTF type information" 378 bool "Generate BTF type information"
379 depends on !DEBUG_INFO_SPLIT && !DEBUG 379 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
380 depends on !GCC_PLUGIN_RANDSTRUCT || C 380 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
381 depends on BPF_SYSCALL 381 depends on BPF_SYSCALL
382 depends on !DEBUG_INFO_DWARF5 || PAHOL 382 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
383 # pahole uses elfutils, which does not 383 # pahole uses elfutils, which does not have support for Hexagon relocations
384 depends on !HEXAGON 384 depends on !HEXAGON
385 help 385 help
386 Generate deduplicated BTF type infor 386 Generate deduplicated BTF type information from DWARF debug info.
387 Turning this on expects presence of 387 Turning this on expects presence of pahole tool, which will convert
388 DWARF type info into equivalent dedu 388 DWARF type info into equivalent deduplicated BTF type info.
389 389
390 config PAHOLE_HAS_SPLIT_BTF 390 config PAHOLE_HAS_SPLIT_BTF
391 def_bool PAHOLE_VERSION >= 119 391 def_bool PAHOLE_VERSION >= 119
392 392
393 config PAHOLE_HAS_BTF_TAG 393 config PAHOLE_HAS_BTF_TAG
394 def_bool PAHOLE_VERSION >= 123 394 def_bool PAHOLE_VERSION >= 123
395 depends on CC_IS_CLANG 395 depends on CC_IS_CLANG
396 help 396 help
397 Decide whether pahole emits btf_tag 397 Decide whether pahole emits btf_tag attributes (btf_type_tag and
398 btf_decl_tag) or not. Currently only 398 btf_decl_tag) or not. Currently only clang compiler implements
399 these attributes, so make the config 399 these attributes, so make the config depend on CC_IS_CLANG.
400 400
401 config PAHOLE_HAS_LANG_EXCLUDE 401 config PAHOLE_HAS_LANG_EXCLUDE
402 def_bool PAHOLE_VERSION >= 124 402 def_bool PAHOLE_VERSION >= 124
403 help 403 help
404 Support for the --lang_exclude flag 404 Support for the --lang_exclude flag which makes pahole exclude
405 compilation units from the supplied 405 compilation units from the supplied language. Used in Kbuild to
406 omit Rust CUs which are not supporte 406 omit Rust CUs which are not supported in version 1.24 of pahole,
407 otherwise it would emit malformed ke 407 otherwise it would emit malformed kernel and module binaries when
408 using DEBUG_INFO_BTF_MODULES. 408 using DEBUG_INFO_BTF_MODULES.
409 409
410 config DEBUG_INFO_BTF_MODULES 410 config DEBUG_INFO_BTF_MODULES
411 bool "Generate BTF type information fo 411 bool "Generate BTF type information for kernel modules"
412 default y 412 default y
413 depends on DEBUG_INFO_BTF && MODULES & 413 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
414 help 414 help
415 Generate compact split BTF type info 415 Generate compact split BTF type information for kernel modules.
416 416
417 config MODULE_ALLOW_BTF_MISMATCH 417 config MODULE_ALLOW_BTF_MISMATCH
418 bool "Allow loading modules with non-m 418 bool "Allow loading modules with non-matching BTF type info"
419 depends on DEBUG_INFO_BTF_MODULES 419 depends on DEBUG_INFO_BTF_MODULES
420 help 420 help
421 For modules whose split BTF does not 421 For modules whose split BTF does not match vmlinux, load without
422 BTF rather than refusing to load. Th 422 BTF rather than refusing to load. The default behavior with
423 module BTF enabled is to reject modu 423 module BTF enabled is to reject modules with such mismatches;
424 this option will still load module B 424 this option will still load module BTF where possible but ignore
425 it when a mismatch is found. 425 it when a mismatch is found.
426 426
427 config GDB_SCRIPTS 427 config GDB_SCRIPTS
428 bool "Provide GDB scripts for kernel d 428 bool "Provide GDB scripts for kernel debugging"
429 help 429 help
430 This creates the required links to G 430 This creates the required links to GDB helper scripts in the
431 build directory. If you load vmlinux 431 build directory. If you load vmlinux into gdb, the helper
432 scripts will be automatically import 432 scripts will be automatically imported by gdb as well, and
433 additional functions are available t 433 additional functions are available to analyze a Linux kernel
434 instance. See Documentation/dev-tool 434 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
435 for further details. 435 for further details.
436 436
437 endif # DEBUG_INFO 437 endif # DEBUG_INFO
438 438
439 config FRAME_WARN 439 config FRAME_WARN
440 int "Warn for stack frames larger than 440 int "Warn for stack frames larger than"
441 range 0 8192 441 range 0 8192
442 default 0 if KMSAN 442 default 0 if KMSAN
443 default 2048 if GCC_PLUGIN_LATENT_ENTR 443 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
444 default 2048 if PARISC 444 default 2048 if PARISC
445 default 1536 if (!64BIT && XTENSA) 445 default 1536 if (!64BIT && XTENSA)
446 default 1280 if KASAN && !64BIT 446 default 1280 if KASAN && !64BIT
447 default 1024 if !64BIT 447 default 1024 if !64BIT
448 default 2048 if 64BIT 448 default 2048 if 64BIT
449 help 449 help
450 Tell the compiler to warn at build t 450 Tell the compiler to warn at build time for stack frames larger than this.
451 Setting this too low will cause a lo 451 Setting this too low will cause a lot of warnings.
452 Setting it to 0 disables the warning 452 Setting it to 0 disables the warning.
453 453
454 config STRIP_ASM_SYMS 454 config STRIP_ASM_SYMS
455 bool "Strip assembler-generated symbol 455 bool "Strip assembler-generated symbols during link"
456 default n 456 default n
457 help 457 help
458 Strip internal assembler-generated s 458 Strip internal assembler-generated symbols during a link (symbols
459 that look like '.Lxxx') so they don' 459 that look like '.Lxxx') so they don't pollute the output of
460 get_wchan() and suchlike. 460 get_wchan() and suchlike.
461 461
462 config READABLE_ASM 462 config READABLE_ASM
463 bool "Generate readable assembler code 463 bool "Generate readable assembler code"
464 depends on DEBUG_KERNEL 464 depends on DEBUG_KERNEL
465 depends on CC_IS_GCC 465 depends on CC_IS_GCC
466 help 466 help
467 Disable some compiler optimizations 467 Disable some compiler optimizations that tend to generate human unreadable
468 assembler output. This may make the 468 assembler output. This may make the kernel slightly slower, but it helps
469 to keep kernel developers who have t 469 to keep kernel developers who have to stare a lot at assembler listings
470 sane. 470 sane.
471 471
472 config HEADERS_INSTALL 472 config HEADERS_INSTALL
473 bool "Install uapi headers to usr/incl 473 bool "Install uapi headers to usr/include"
474 depends on !UML 474 depends on !UML
475 help 475 help
476 This option will install uapi header 476 This option will install uapi headers (headers exported to user-space)
477 into the usr/include directory for u 477 into the usr/include directory for use during the kernel build.
478 This is unneeded for building the ke 478 This is unneeded for building the kernel itself, but needed for some
479 user-space program samples. It is al 479 user-space program samples. It is also needed by some features such
480 as uapi header sanity checks. 480 as uapi header sanity checks.
481 481
482 config DEBUG_SECTION_MISMATCH 482 config DEBUG_SECTION_MISMATCH
483 bool "Enable full Section mismatch ana 483 bool "Enable full Section mismatch analysis"
484 depends on CC_IS_GCC 484 depends on CC_IS_GCC
485 help 485 help
486 The section mismatch analysis checks 486 The section mismatch analysis checks if there are illegal
487 references from one section to anoth 487 references from one section to another section.
488 During linktime or runtime, some sec 488 During linktime or runtime, some sections are dropped;
489 any use of code/data previously in t 489 any use of code/data previously in these sections would
490 most likely result in an oops. 490 most likely result in an oops.
491 In the code, functions and variables 491 In the code, functions and variables are annotated with
492 __init,, etc. (see the full list in 492 __init,, etc. (see the full list in include/linux/init.h),
493 which results in the code/data being 493 which results in the code/data being placed in specific sections.
494 The section mismatch analysis is alw 494 The section mismatch analysis is always performed after a full
495 kernel build, and enabling this opti 495 kernel build, and enabling this option causes the following
496 additional step to occur: 496 additional step to occur:
497 - Add the option -fno-inline-functio 497 - Add the option -fno-inline-functions-called-once to gcc commands.
498 When inlining a function annotated 498 When inlining a function annotated with __init in a non-init
499 function, we would lose the sectio 499 function, we would lose the section information and thus
500 the analysis would not catch the i 500 the analysis would not catch the illegal reference.
501 This option tells gcc to inline le 501 This option tells gcc to inline less (but it does result in
502 a larger kernel). 502 a larger kernel).
503 503
504 config SECTION_MISMATCH_WARN_ONLY 504 config SECTION_MISMATCH_WARN_ONLY
505 bool "Make section mismatch errors non 505 bool "Make section mismatch errors non-fatal"
506 default y 506 default y
507 help 507 help
508 If you say N here, the build process 508 If you say N here, the build process will fail if there are any
509 section mismatch, instead of just th 509 section mismatch, instead of just throwing warnings.
510 510
511 If unsure, say Y. 511 If unsure, say Y.
512 512
513 config DEBUG_FORCE_FUNCTION_ALIGN_64B 513 config DEBUG_FORCE_FUNCTION_ALIGN_64B
514 bool "Force all function address 64B a 514 bool "Force all function address 64B aligned"
515 depends on EXPERT && (X86_64 || ARM64 515 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
516 select FUNCTION_ALIGNMENT_64B 516 select FUNCTION_ALIGNMENT_64B
517 help 517 help
518 There are cases that a commit from o 518 There are cases that a commit from one domain changes the function
519 address alignment of other domains, 519 address alignment of other domains, and cause magic performance
520 bump (regression or improvement). En 520 bump (regression or improvement). Enable this option will help to
521 verify if the bump is caused by func 521 verify if the bump is caused by function alignment changes, while
522 it will slightly increase the kernel 522 it will slightly increase the kernel size and affect icache usage.
523 523
524 It is mainly for debug and performan 524 It is mainly for debug and performance tuning use.
525 525
526 # 526 #
527 # Select this config option from the architect 527 # Select this config option from the architecture Kconfig, if it
528 # is preferred to always offer frame pointers 528 # is preferred to always offer frame pointers as a config
529 # option on the architecture (regardless of KE 529 # option on the architecture (regardless of KERNEL_DEBUG):
530 # 530 #
531 config ARCH_WANT_FRAME_POINTERS 531 config ARCH_WANT_FRAME_POINTERS
532 bool 532 bool
533 533
534 config FRAME_POINTER 534 config FRAME_POINTER
535 bool "Compile the kernel with frame po 535 bool "Compile the kernel with frame pointers"
536 depends on DEBUG_KERNEL && (M68K || UM 536 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
537 default y if (DEBUG_INFO && UML) || AR 537 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
538 help 538 help
539 If you say Y here the resulting kern 539 If you say Y here the resulting kernel image will be slightly
540 larger and slower, but it gives very 540 larger and slower, but it gives very useful debugging information
541 in case of kernel bugs. (precise oop 541 in case of kernel bugs. (precise oopses/stacktraces/warnings)
542 542
543 config OBJTOOL 543 config OBJTOOL
544 bool 544 bool
545 545
546 config STACK_VALIDATION 546 config STACK_VALIDATION
547 bool "Compile-time stack metadata vali 547 bool "Compile-time stack metadata validation"
548 depends on HAVE_STACK_VALIDATION && UN 548 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
549 select OBJTOOL 549 select OBJTOOL
550 default n 550 default n
551 help 551 help
552 Validate frame pointer rules at comp 552 Validate frame pointer rules at compile-time. This helps ensure that
553 runtime stack traces are more reliab 553 runtime stack traces are more reliable.
554 554
555 For more information, see 555 For more information, see
556 tools/objtool/Documentation/objtool. 556 tools/objtool/Documentation/objtool.txt.
557 557
558 config NOINSTR_VALIDATION 558 config NOINSTR_VALIDATION
559 bool 559 bool
560 depends on HAVE_NOINSTR_VALIDATION && 560 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
561 select OBJTOOL 561 select OBJTOOL
562 default y 562 default y
563 563
564 config VMLINUX_MAP 564 config VMLINUX_MAP
565 bool "Generate vmlinux.map file when l 565 bool "Generate vmlinux.map file when linking"
566 depends on EXPERT 566 depends on EXPERT
567 help 567 help
568 Selecting this option will pass "-Ma 568 Selecting this option will pass "-Map=vmlinux.map" to ld
569 when linking vmlinux. That file can 569 when linking vmlinux. That file can be useful for verifying
570 and debugging magic section games, a 570 and debugging magic section games, and for seeing which
571 pieces of code get eliminated with 571 pieces of code get eliminated with
572 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION 572 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
573 573
574 config DEBUG_FORCE_WEAK_PER_CPU 574 config DEBUG_FORCE_WEAK_PER_CPU
575 bool "Force weak per-cpu definitions" 575 bool "Force weak per-cpu definitions"
576 depends on DEBUG_KERNEL 576 depends on DEBUG_KERNEL
577 help 577 help
578 s390 and alpha require percpu variab 578 s390 and alpha require percpu variables in modules to be
579 defined weak to work around addressi 579 defined weak to work around addressing range issue which
580 puts the following two restrictions 580 puts the following two restrictions on percpu variable
581 definitions. 581 definitions.
582 582
583 1. percpu symbols must be unique whe 583 1. percpu symbols must be unique whether static or not
584 2. percpu variables can't be defined 584 2. percpu variables can't be defined inside a function
585 585
586 To ensure that generic code follows 586 To ensure that generic code follows the above rules, this
587 option forces all percpu variables t 587 option forces all percpu variables to be defined as weak.
588 588
589 endmenu # "Compiler options" 589 endmenu # "Compiler options"
590 590
591 menu "Generic Kernel Debugging Instruments" 591 menu "Generic Kernel Debugging Instruments"
592 592
593 config MAGIC_SYSRQ 593 config MAGIC_SYSRQ
594 bool "Magic SysRq key" 594 bool "Magic SysRq key"
595 depends on !UML 595 depends on !UML
596 help 596 help
597 If you say Y here, you will have som 597 If you say Y here, you will have some control over the system even
598 if the system crashes for example du 598 if the system crashes for example during kernel debugging (e.g., you
599 will be able to flush the buffer cac 599 will be able to flush the buffer cache to disk, reboot the system
600 immediately or dump some status info 600 immediately or dump some status information). This is accomplished
601 by pressing various keys while holdi 601 by pressing various keys while holding SysRq (Alt+PrintScreen). It
602 also works on a serial console (on P 602 also works on a serial console (on PC hardware at least), if you
603 send a BREAK and then within 5 secon 603 send a BREAK and then within 5 seconds a command keypress. The
604 keys are documented in <file:Documen 604 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
605 Don't say Y unless you really know w 605 Don't say Y unless you really know what this hack does.
606 606
607 config MAGIC_SYSRQ_DEFAULT_ENABLE 607 config MAGIC_SYSRQ_DEFAULT_ENABLE
608 hex "Enable magic SysRq key functions 608 hex "Enable magic SysRq key functions by default"
609 depends on MAGIC_SYSRQ 609 depends on MAGIC_SYSRQ
610 default 0x1 610 default 0x1
611 help 611 help
612 Specifies which SysRq key functions 612 Specifies which SysRq key functions are enabled by default.
613 This may be set to 1 or 0 to enable 613 This may be set to 1 or 0 to enable or disable them all, or
614 to a bitmask as described in Documen 614 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
615 615
616 config MAGIC_SYSRQ_SERIAL 616 config MAGIC_SYSRQ_SERIAL
617 bool "Enable magic SysRq key over seri 617 bool "Enable magic SysRq key over serial"
618 depends on MAGIC_SYSRQ 618 depends on MAGIC_SYSRQ
619 default y 619 default y
620 help 620 help
621 Many embedded boards have a disconne 621 Many embedded boards have a disconnected TTL level serial which can
622 generate some garbage that can lead 622 generate some garbage that can lead to spurious false sysrq detects.
623 This option allows you to decide whe 623 This option allows you to decide whether you want to enable the
624 magic SysRq key. 624 magic SysRq key.
625 625
626 config MAGIC_SYSRQ_SERIAL_SEQUENCE 626 config MAGIC_SYSRQ_SERIAL_SEQUENCE
627 string "Char sequence that enables mag 627 string "Char sequence that enables magic SysRq over serial"
628 depends on MAGIC_SYSRQ_SERIAL 628 depends on MAGIC_SYSRQ_SERIAL
629 default "" 629 default ""
630 help 630 help
631 Specifies a sequence of characters t 631 Specifies a sequence of characters that can follow BREAK to enable
632 SysRq on a serial console. 632 SysRq on a serial console.
633 633
634 If unsure, leave an empty string and 634 If unsure, leave an empty string and the option will not be enabled.
635 635
636 config DEBUG_FS 636 config DEBUG_FS
637 bool "Debug Filesystem" 637 bool "Debug Filesystem"
638 help 638 help
639 debugfs is a virtual file system tha 639 debugfs is a virtual file system that kernel developers use to put
640 debugging files into. Enable this o 640 debugging files into. Enable this option to be able to read and
641 write to these files. 641 write to these files.
642 642
643 For detailed documentation on the de 643 For detailed documentation on the debugfs API, see
644 Documentation/filesystems/. 644 Documentation/filesystems/.
645 645
646 If unsure, say N. 646 If unsure, say N.
647 647
648 choice 648 choice
649 prompt "Debugfs default access" 649 prompt "Debugfs default access"
650 depends on DEBUG_FS 650 depends on DEBUG_FS
651 default DEBUG_FS_ALLOW_ALL 651 default DEBUG_FS_ALLOW_ALL
652 help 652 help
653 This selects the default access rest 653 This selects the default access restrictions for debugfs.
654 It can be overridden with kernel com 654 It can be overridden with kernel command line option
655 debugfs=[on,no-mount,off]. The restr 655 debugfs=[on,no-mount,off]. The restrictions apply for API access
656 and filesystem registration. 656 and filesystem registration.
657 657
658 config DEBUG_FS_ALLOW_ALL 658 config DEBUG_FS_ALLOW_ALL
659 bool "Access normal" 659 bool "Access normal"
660 help 660 help
661 No restrictions apply. Both API and 661 No restrictions apply. Both API and filesystem registration
662 is on. This is the normal default op 662 is on. This is the normal default operation.
663 663
664 config DEBUG_FS_DISALLOW_MOUNT 664 config DEBUG_FS_DISALLOW_MOUNT
665 bool "Do not register debugfs as files 665 bool "Do not register debugfs as filesystem"
666 help 666 help
667 The API is open but filesystem is no 667 The API is open but filesystem is not loaded. Clients can still do
668 their work and read with debug tools 668 their work and read with debug tools that do not need
669 debugfs filesystem. 669 debugfs filesystem.
670 670
671 config DEBUG_FS_ALLOW_NONE 671 config DEBUG_FS_ALLOW_NONE
672 bool "No access" 672 bool "No access"
673 help 673 help
674 Access is off. Clients get -PERM whe 674 Access is off. Clients get -PERM when trying to create nodes in
675 debugfs tree and debugfs is not regi 675 debugfs tree and debugfs is not registered as a filesystem.
676 Client can then back-off or continue 676 Client can then back-off or continue without debugfs access.
677 677
678 endchoice 678 endchoice
679 679
680 source "lib/Kconfig.kgdb" 680 source "lib/Kconfig.kgdb"
681 source "lib/Kconfig.ubsan" 681 source "lib/Kconfig.ubsan"
682 source "lib/Kconfig.kcsan" 682 source "lib/Kconfig.kcsan"
683 683
684 endmenu 684 endmenu
685 685
686 menu "Networking Debugging" 686 menu "Networking Debugging"
687 687
688 source "net/Kconfig.debug" 688 source "net/Kconfig.debug"
689 689
690 endmenu # "Networking Debugging" 690 endmenu # "Networking Debugging"
691 691
692 menu "Memory Debugging" 692 menu "Memory Debugging"
693 693
694 source "mm/Kconfig.debug" 694 source "mm/Kconfig.debug"
695 695
696 config DEBUG_OBJECTS 696 config DEBUG_OBJECTS
697 bool "Debug object operations" 697 bool "Debug object operations"
698 depends on DEBUG_KERNEL 698 depends on DEBUG_KERNEL
699 help 699 help
700 If you say Y here, additional code w 700 If you say Y here, additional code will be inserted into the
701 kernel to track the life time of var 701 kernel to track the life time of various objects and validate
702 the operations on those objects. 702 the operations on those objects.
703 703
704 config DEBUG_OBJECTS_SELFTEST 704 config DEBUG_OBJECTS_SELFTEST
705 bool "Debug objects selftest" 705 bool "Debug objects selftest"
706 depends on DEBUG_OBJECTS 706 depends on DEBUG_OBJECTS
707 help 707 help
708 This enables the selftest of the obj 708 This enables the selftest of the object debug code.
709 709
710 config DEBUG_OBJECTS_FREE 710 config DEBUG_OBJECTS_FREE
711 bool "Debug objects in freed memory" 711 bool "Debug objects in freed memory"
712 depends on DEBUG_OBJECTS 712 depends on DEBUG_OBJECTS
713 help 713 help
714 This enables checks whether a k/v fr 714 This enables checks whether a k/v free operation frees an area
715 which contains an object which has n 715 which contains an object which has not been deactivated
716 properly. This can make kmalloc/kfre 716 properly. This can make kmalloc/kfree-intensive workloads
717 much slower. 717 much slower.
718 718
719 config DEBUG_OBJECTS_TIMERS 719 config DEBUG_OBJECTS_TIMERS
720 bool "Debug timer objects" 720 bool "Debug timer objects"
721 depends on DEBUG_OBJECTS 721 depends on DEBUG_OBJECTS
722 help 722 help
723 If you say Y here, additional code w 723 If you say Y here, additional code will be inserted into the
724 timer routines to track the life tim 724 timer routines to track the life time of timer objects and
725 validate the timer operations. 725 validate the timer operations.
726 726
727 config DEBUG_OBJECTS_WORK 727 config DEBUG_OBJECTS_WORK
728 bool "Debug work objects" 728 bool "Debug work objects"
729 depends on DEBUG_OBJECTS 729 depends on DEBUG_OBJECTS
730 help 730 help
731 If you say Y here, additional code w 731 If you say Y here, additional code will be inserted into the
732 work queue routines to track the lif 732 work queue routines to track the life time of work objects and
733 validate the work operations. 733 validate the work operations.
734 734
735 config DEBUG_OBJECTS_RCU_HEAD 735 config DEBUG_OBJECTS_RCU_HEAD
736 bool "Debug RCU callbacks objects" 736 bool "Debug RCU callbacks objects"
737 depends on DEBUG_OBJECTS 737 depends on DEBUG_OBJECTS
738 help 738 help
739 Enable this to turn on debugging of 739 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
740 740
741 config DEBUG_OBJECTS_PERCPU_COUNTER 741 config DEBUG_OBJECTS_PERCPU_COUNTER
742 bool "Debug percpu counter objects" 742 bool "Debug percpu counter objects"
743 depends on DEBUG_OBJECTS 743 depends on DEBUG_OBJECTS
744 help 744 help
745 If you say Y here, additional code w 745 If you say Y here, additional code will be inserted into the
746 percpu counter routines to track the 746 percpu counter routines to track the life time of percpu counter
747 objects and validate the percpu coun 747 objects and validate the percpu counter operations.
748 748
749 config DEBUG_OBJECTS_ENABLE_DEFAULT 749 config DEBUG_OBJECTS_ENABLE_DEFAULT
750 int "debug_objects bootup default valu 750 int "debug_objects bootup default value (0-1)"
751 range 0 1 751 range 0 1
752 default "1" 752 default "1"
753 depends on DEBUG_OBJECTS 753 depends on DEBUG_OBJECTS
754 help 754 help
755 Debug objects boot parameter default 755 Debug objects boot parameter default value
756 756
757 config SHRINKER_DEBUG 757 config SHRINKER_DEBUG
758 bool "Enable shrinker debugging suppor 758 bool "Enable shrinker debugging support"
759 depends on DEBUG_FS 759 depends on DEBUG_FS
760 help 760 help
761 Say Y to enable the shrinker debugfs 761 Say Y to enable the shrinker debugfs interface which provides
762 visibility into the kernel memory sh 762 visibility into the kernel memory shrinkers subsystem.
763 Disable it to avoid an extra memory 763 Disable it to avoid an extra memory footprint.
764 764
765 config DEBUG_STACK_USAGE 765 config DEBUG_STACK_USAGE
766 bool "Stack utilization instrumentatio 766 bool "Stack utilization instrumentation"
767 depends on DEBUG_KERNEL 767 depends on DEBUG_KERNEL
768 help 768 help
769 Enables the display of the minimum a 769 Enables the display of the minimum amount of free stack which each
770 task has ever had available in the s 770 task has ever had available in the sysrq-T and sysrq-P debug output.
771 Also emits a message to dmesg when a 771 Also emits a message to dmesg when a process exits if that process
772 used more stack space than previousl 772 used more stack space than previously exiting processes.
773 773
774 This option will slow down process c 774 This option will slow down process creation somewhat.
775 775
776 config SCHED_STACK_END_CHECK 776 config SCHED_STACK_END_CHECK
777 bool "Detect stack corruption on calls 777 bool "Detect stack corruption on calls to schedule()"
778 depends on DEBUG_KERNEL 778 depends on DEBUG_KERNEL
779 default n 779 default n
780 help 780 help
781 This option checks for a stack overr 781 This option checks for a stack overrun on calls to schedule().
782 If the stack end location is found t 782 If the stack end location is found to be over written always panic as
783 the content of the corrupted region 783 the content of the corrupted region can no longer be trusted.
784 This is to ensure no erroneous behav 784 This is to ensure no erroneous behaviour occurs which could result in
785 data corruption or a sporadic crash 785 data corruption or a sporadic crash at a later stage once the region
786 is examined. The runtime overhead in 786 is examined. The runtime overhead introduced is minimal.
787 787
788 config ARCH_HAS_DEBUG_VM_PGTABLE 788 config ARCH_HAS_DEBUG_VM_PGTABLE
789 bool 789 bool
790 help 790 help
791 An architecture should select this w 791 An architecture should select this when it can successfully
792 build and run DEBUG_VM_PGTABLE. 792 build and run DEBUG_VM_PGTABLE.
793 793
794 config DEBUG_VM_IRQSOFF 794 config DEBUG_VM_IRQSOFF
795 def_bool DEBUG_VM && !PREEMPT_RT 795 def_bool DEBUG_VM && !PREEMPT_RT
796 796
797 config DEBUG_VM 797 config DEBUG_VM
798 bool "Debug VM" 798 bool "Debug VM"
799 depends on DEBUG_KERNEL 799 depends on DEBUG_KERNEL
800 help 800 help
801 Enable this to turn on extended chec 801 Enable this to turn on extended checks in the virtual-memory system
802 that may impact performance. 802 that may impact performance.
803 803
804 If unsure, say N. 804 If unsure, say N.
805 805
806 config DEBUG_VM_SHOOT_LAZIES 806 config DEBUG_VM_SHOOT_LAZIES
807 bool "Debug MMU_LAZY_TLB_SHOOTDOWN imp 807 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
808 depends on DEBUG_VM 808 depends on DEBUG_VM
809 depends on MMU_LAZY_TLB_SHOOTDOWN 809 depends on MMU_LAZY_TLB_SHOOTDOWN
810 help 810 help
811 Enable additional IPIs that ensure l 811 Enable additional IPIs that ensure lazy tlb mm references are removed
812 before the mm is freed. 812 before the mm is freed.
813 813
814 If unsure, say N. 814 If unsure, say N.
815 815
816 config DEBUG_VM_MAPLE_TREE 816 config DEBUG_VM_MAPLE_TREE
817 bool "Debug VM maple trees" 817 bool "Debug VM maple trees"
818 depends on DEBUG_VM 818 depends on DEBUG_VM
819 select DEBUG_MAPLE_TREE 819 select DEBUG_MAPLE_TREE
820 help 820 help
821 Enable VM maple tree debugging infor 821 Enable VM maple tree debugging information and extra validations.
822 822
823 If unsure, say N. 823 If unsure, say N.
824 824
825 config DEBUG_VM_RB 825 config DEBUG_VM_RB
826 bool "Debug VM red-black trees" 826 bool "Debug VM red-black trees"
827 depends on DEBUG_VM 827 depends on DEBUG_VM
828 help 828 help
829 Enable VM red-black tree debugging i 829 Enable VM red-black tree debugging information and extra validations.
830 830
831 If unsure, say N. 831 If unsure, say N.
832 832
833 config DEBUG_VM_PGFLAGS 833 config DEBUG_VM_PGFLAGS
834 bool "Debug page-flags operations" 834 bool "Debug page-flags operations"
835 depends on DEBUG_VM 835 depends on DEBUG_VM
836 help 836 help
837 Enables extra validation on page fla 837 Enables extra validation on page flags operations.
838 838
839 If unsure, say N. 839 If unsure, say N.
840 840
841 config DEBUG_VM_PGTABLE 841 config DEBUG_VM_PGTABLE
842 bool "Debug arch page table for semant 842 bool "Debug arch page table for semantics compliance"
843 depends on MMU 843 depends on MMU
844 depends on ARCH_HAS_DEBUG_VM_PGTABLE 844 depends on ARCH_HAS_DEBUG_VM_PGTABLE
845 default y if DEBUG_VM 845 default y if DEBUG_VM
846 help 846 help
847 This option provides a debug method 847 This option provides a debug method which can be used to test
848 architecture page table helper funct 848 architecture page table helper functions on various platforms in
849 verifying if they comply with expect 849 verifying if they comply with expected generic MM semantics. This
850 will help architecture code in makin 850 will help architecture code in making sure that any changes or
851 new additions of these helpers still 851 new additions of these helpers still conform to expected
852 semantics of the generic MM. Platfor 852 semantics of the generic MM. Platforms will have to opt in for
853 this through ARCH_HAS_DEBUG_VM_PGTAB 853 this through ARCH_HAS_DEBUG_VM_PGTABLE.
854 854
855 If unsure, say N. 855 If unsure, say N.
856 856
857 config ARCH_HAS_DEBUG_VIRTUAL 857 config ARCH_HAS_DEBUG_VIRTUAL
858 bool 858 bool
859 859
860 config DEBUG_VIRTUAL 860 config DEBUG_VIRTUAL
861 bool "Debug VM translations" 861 bool "Debug VM translations"
862 depends on DEBUG_KERNEL && ARCH_HAS_DE 862 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
863 help 863 help
864 Enable some costly sanity checks in 864 Enable some costly sanity checks in virtual to page code. This can
865 catch mistakes with virt_to_page() a 865 catch mistakes with virt_to_page() and friends.
866 866
867 If unsure, say N. 867 If unsure, say N.
868 868
869 config DEBUG_NOMMU_REGIONS 869 config DEBUG_NOMMU_REGIONS
870 bool "Debug the global anon/private NO 870 bool "Debug the global anon/private NOMMU mapping region tree"
871 depends on DEBUG_KERNEL && !MMU 871 depends on DEBUG_KERNEL && !MMU
872 help 872 help
873 This option causes the global tree o 873 This option causes the global tree of anonymous and private mapping
874 regions to be regularly checked for 874 regions to be regularly checked for invalid topology.
875 875
876 config DEBUG_MEMORY_INIT 876 config DEBUG_MEMORY_INIT
877 bool "Debug memory initialisation" if 877 bool "Debug memory initialisation" if EXPERT
878 default !EXPERT 878 default !EXPERT
879 help 879 help
880 Enable this for additional checks du 880 Enable this for additional checks during memory initialisation.
881 The sanity checks verify aspects of 881 The sanity checks verify aspects of the VM such as the memory model
882 and other information provided by th 882 and other information provided by the architecture. Verbose
883 information will be printed at KERN_ 883 information will be printed at KERN_DEBUG loglevel depending
884 on the mminit_loglevel= command-line 884 on the mminit_loglevel= command-line option.
885 885
886 If unsure, say Y 886 If unsure, say Y
887 887
888 config MEMORY_NOTIFIER_ERROR_INJECT 888 config MEMORY_NOTIFIER_ERROR_INJECT
889 tristate "Memory hotplug notifier erro 889 tristate "Memory hotplug notifier error injection module"
890 depends on MEMORY_HOTPLUG && NOTIFIER_ 890 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
891 help 891 help
892 This option provides the ability to 892 This option provides the ability to inject artificial errors to
893 memory hotplug notifier chain callba 893 memory hotplug notifier chain callbacks. It is controlled through
894 debugfs interface under /sys/kernel/ 894 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
895 895
896 If the notifier call chain should be 896 If the notifier call chain should be failed with some events
897 notified, write the error code to "a 897 notified, write the error code to "actions/<notifier event>/error".
898 898
899 Example: Inject memory hotplug offli 899 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
900 900
901 # cd /sys/kernel/debug/notifier-erro 901 # cd /sys/kernel/debug/notifier-error-inject/memory
902 # echo -12 > actions/MEM_GOING_OFFLI 902 # echo -12 > actions/MEM_GOING_OFFLINE/error
903 # echo offline > /sys/devices/system 903 # echo offline > /sys/devices/system/memory/memoryXXX/state
904 bash: echo: write error: Cannot allo 904 bash: echo: write error: Cannot allocate memory
905 905
906 To compile this code as a module, ch 906 To compile this code as a module, choose M here: the module will
907 be called memory-notifier-error-inje 907 be called memory-notifier-error-inject.
908 908
909 If unsure, say N. 909 If unsure, say N.
910 910
911 config DEBUG_PER_CPU_MAPS 911 config DEBUG_PER_CPU_MAPS
912 bool "Debug access to per_cpu maps" 912 bool "Debug access to per_cpu maps"
913 depends on DEBUG_KERNEL 913 depends on DEBUG_KERNEL
914 depends on SMP 914 depends on SMP
915 help 915 help
916 Say Y to verify that the per_cpu map 916 Say Y to verify that the per_cpu map being accessed has
917 been set up. This adds a fair amount 917 been set up. This adds a fair amount of code to kernel memory
918 and decreases performance. 918 and decreases performance.
919 919
920 Say N if unsure. 920 Say N if unsure.
921 921
922 config DEBUG_KMAP_LOCAL 922 config DEBUG_KMAP_LOCAL
923 bool "Debug kmap_local temporary mappi 923 bool "Debug kmap_local temporary mappings"
924 depends on DEBUG_KERNEL && KMAP_LOCAL 924 depends on DEBUG_KERNEL && KMAP_LOCAL
925 help 925 help
926 This option enables additional error 926 This option enables additional error checking for the kmap_local
927 infrastructure. Disable for product 927 infrastructure. Disable for production use.
928 928
929 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 929 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
930 bool 930 bool
931 931
932 config DEBUG_KMAP_LOCAL_FORCE_MAP 932 config DEBUG_KMAP_LOCAL_FORCE_MAP
933 bool "Enforce kmap_local temporary map 933 bool "Enforce kmap_local temporary mappings"
934 depends on DEBUG_KERNEL && ARCH_SUPPOR 934 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
935 select KMAP_LOCAL 935 select KMAP_LOCAL
936 select DEBUG_KMAP_LOCAL 936 select DEBUG_KMAP_LOCAL
937 help 937 help
938 This option enforces temporary mappi 938 This option enforces temporary mappings through the kmap_local
939 mechanism for non-highmem pages and 939 mechanism for non-highmem pages and on non-highmem systems.
940 Disable this for production systems! 940 Disable this for production systems!
941 941
942 config DEBUG_HIGHMEM 942 config DEBUG_HIGHMEM
943 bool "Highmem debugging" 943 bool "Highmem debugging"
944 depends on DEBUG_KERNEL && HIGHMEM 944 depends on DEBUG_KERNEL && HIGHMEM
945 select DEBUG_KMAP_LOCAL_FORCE_MAP if A 945 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
946 select DEBUG_KMAP_LOCAL 946 select DEBUG_KMAP_LOCAL
947 help 947 help
948 This option enables additional error 948 This option enables additional error checking for high memory
949 systems. Disable for production sys 949 systems. Disable for production systems.
950 950
951 config HAVE_DEBUG_STACKOVERFLOW 951 config HAVE_DEBUG_STACKOVERFLOW
952 bool 952 bool
953 953
954 config DEBUG_STACKOVERFLOW 954 config DEBUG_STACKOVERFLOW
955 bool "Check for stack overflows" 955 bool "Check for stack overflows"
956 depends on DEBUG_KERNEL && HAVE_DEBUG_ 956 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
957 help 957 help
958 Say Y here if you want to check for 958 Say Y here if you want to check for overflows of kernel, IRQ
959 and exception stacks (if your archit 959 and exception stacks (if your architecture uses them). This
960 option will show detailed messages i 960 option will show detailed messages if free stack space drops
961 below a certain limit. 961 below a certain limit.
962 962
963 These kinds of bugs usually occur wh 963 These kinds of bugs usually occur when call-chains in the
964 kernel get too deep, especially when 964 kernel get too deep, especially when interrupts are
965 involved. 965 involved.
966 966
967 Use this in cases where you see appa 967 Use this in cases where you see apparently random memory
968 corruption, especially if it appears 968 corruption, especially if it appears in 'struct thread_info'
969 969
970 If in doubt, say "N". 970 If in doubt, say "N".
971 971
972 config CODE_TAGGING 972 config CODE_TAGGING
973 bool 973 bool
974 select KALLSYMS 974 select KALLSYMS
975 975
976 config MEM_ALLOC_PROFILING 976 config MEM_ALLOC_PROFILING
977 bool "Enable memory allocation profili 977 bool "Enable memory allocation profiling"
978 default n 978 default n
979 depends on PROC_FS 979 depends on PROC_FS
980 depends on !DEBUG_FORCE_WEAK_PER_CPU 980 depends on !DEBUG_FORCE_WEAK_PER_CPU
981 select CODE_TAGGING 981 select CODE_TAGGING
982 select PAGE_EXTENSION 982 select PAGE_EXTENSION
983 select SLAB_OBJ_EXT 983 select SLAB_OBJ_EXT
984 help 984 help
985 Track allocation source code and rec 985 Track allocation source code and record total allocation size
986 initiated at that code location. The 986 initiated at that code location. The mechanism can be used to track
987 memory leaks with a low performance 987 memory leaks with a low performance and memory impact.
988 988
989 config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT 989 config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
990 bool "Enable memory allocation profili 990 bool "Enable memory allocation profiling by default"
991 default y 991 default y
992 depends on MEM_ALLOC_PROFILING 992 depends on MEM_ALLOC_PROFILING
993 993
994 config MEM_ALLOC_PROFILING_DEBUG 994 config MEM_ALLOC_PROFILING_DEBUG
995 bool "Memory allocation profiler debug 995 bool "Memory allocation profiler debugging"
996 default n 996 default n
997 depends on MEM_ALLOC_PROFILING 997 depends on MEM_ALLOC_PROFILING
998 select MEM_ALLOC_PROFILING_ENABLED_BY_ 998 select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
999 help 999 help
1000 Adds warnings with helpful error me 1000 Adds warnings with helpful error messages for memory allocation
1001 profiling. 1001 profiling.
1002 1002
1003 source "lib/Kconfig.kasan" 1003 source "lib/Kconfig.kasan"
1004 source "lib/Kconfig.kfence" 1004 source "lib/Kconfig.kfence"
1005 source "lib/Kconfig.kmsan" 1005 source "lib/Kconfig.kmsan"
1006 1006
1007 endmenu # "Memory Debugging" 1007 endmenu # "Memory Debugging"
1008 1008
1009 config DEBUG_SHIRQ 1009 config DEBUG_SHIRQ
1010 bool "Debug shared IRQ handlers" 1010 bool "Debug shared IRQ handlers"
1011 depends on DEBUG_KERNEL 1011 depends on DEBUG_KERNEL
1012 help 1012 help
1013 Enable this to generate a spurious 1013 Enable this to generate a spurious interrupt just before a shared
1014 interrupt handler is deregistered ( 1014 interrupt handler is deregistered (generating one when registering
1015 is currently disabled). Drivers nee 1015 is currently disabled). Drivers need to handle this correctly. Some
1016 don't and need to be caught. 1016 don't and need to be caught.
1017 1017
1018 menu "Debug Oops, Lockups and Hangs" 1018 menu "Debug Oops, Lockups and Hangs"
1019 1019
1020 config PANIC_ON_OOPS 1020 config PANIC_ON_OOPS
1021 bool "Panic on Oops" 1021 bool "Panic on Oops"
1022 help 1022 help
1023 Say Y here to enable the kernel to 1023 Say Y here to enable the kernel to panic when it oopses. This
1024 has the same effect as setting oops 1024 has the same effect as setting oops=panic on the kernel command
1025 line. 1025 line.
1026 1026
1027 This feature is useful to ensure th 1027 This feature is useful to ensure that the kernel does not do
1028 anything erroneous after an oops wh 1028 anything erroneous after an oops which could result in data
1029 corruption or other issues. 1029 corruption or other issues.
1030 1030
1031 Say N if unsure. 1031 Say N if unsure.
1032 1032
1033 config PANIC_ON_OOPS_VALUE 1033 config PANIC_ON_OOPS_VALUE
1034 int 1034 int
1035 range 0 1 1035 range 0 1
1036 default 0 if !PANIC_ON_OOPS 1036 default 0 if !PANIC_ON_OOPS
1037 default 1 if PANIC_ON_OOPS 1037 default 1 if PANIC_ON_OOPS
1038 1038
1039 config PANIC_TIMEOUT 1039 config PANIC_TIMEOUT
1040 int "panic timeout" 1040 int "panic timeout"
1041 default 0 1041 default 0
1042 help 1042 help
1043 Set the timeout value (in seconds) 1043 Set the timeout value (in seconds) until a reboot occurs when
1044 the kernel panics. If n = 0, then w 1044 the kernel panics. If n = 0, then we wait forever. A timeout
1045 value n > 0 will wait n seconds bef 1045 value n > 0 will wait n seconds before rebooting, while a timeout
1046 value n < 0 will reboot immediately 1046 value n < 0 will reboot immediately. This setting can be overridden
1047 with the kernel command line option 1047 with the kernel command line option panic=, and from userspace via
1048 /proc/sys/kernel/panic. 1048 /proc/sys/kernel/panic.
1049 1049
1050 config LOCKUP_DETECTOR 1050 config LOCKUP_DETECTOR
1051 bool 1051 bool
1052 1052
1053 config SOFTLOCKUP_DETECTOR 1053 config SOFTLOCKUP_DETECTOR
1054 bool "Detect Soft Lockups" 1054 bool "Detect Soft Lockups"
1055 depends on DEBUG_KERNEL && !S390 1055 depends on DEBUG_KERNEL && !S390
1056 select LOCKUP_DETECTOR 1056 select LOCKUP_DETECTOR
1057 help 1057 help
1058 Say Y here to enable the kernel to 1058 Say Y here to enable the kernel to act as a watchdog to detect
1059 soft lockups. 1059 soft lockups.
1060 1060
1061 Softlockups are bugs that cause the 1061 Softlockups are bugs that cause the kernel to loop in kernel
1062 mode for more than 20 seconds, with 1062 mode for more than 20 seconds, without giving other tasks a
1063 chance to run. The current stack t 1063 chance to run. The current stack trace is displayed upon
1064 detection and the system will stay 1064 detection and the system will stay locked up.
1065 1065
1066 config SOFTLOCKUP_DETECTOR_INTR_STORM 1066 config SOFTLOCKUP_DETECTOR_INTR_STORM
1067 bool "Detect Interrupt Storm in Soft 1067 bool "Detect Interrupt Storm in Soft Lockups"
1068 depends on SOFTLOCKUP_DETECTOR && IRQ 1068 depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1069 select GENERIC_IRQ_STAT_SNAPSHOT 1069 select GENERIC_IRQ_STAT_SNAPSHOT
1070 default y if NR_CPUS <= 128 1070 default y if NR_CPUS <= 128
1071 help 1071 help
1072 Say Y here to enable the kernel to 1072 Say Y here to enable the kernel to detect interrupt storm
1073 during "soft lockups". 1073 during "soft lockups".
1074 1074
1075 "soft lockups" can be caused by a v 1075 "soft lockups" can be caused by a variety of reasons. If one is
1076 caused by an interrupt storm, then 1076 caused by an interrupt storm, then the storming interrupts will not
1077 be on the callstack. To detect this 1077 be on the callstack. To detect this case, it is necessary to report
1078 the CPU stats and the interrupt cou 1078 the CPU stats and the interrupt counts during the "soft lockups".
1079 1079
1080 config BOOTPARAM_SOFTLOCKUP_PANIC 1080 config BOOTPARAM_SOFTLOCKUP_PANIC
1081 bool "Panic (Reboot) On Soft Lockups" 1081 bool "Panic (Reboot) On Soft Lockups"
1082 depends on SOFTLOCKUP_DETECTOR 1082 depends on SOFTLOCKUP_DETECTOR
1083 help 1083 help
1084 Say Y here to enable the kernel to 1084 Say Y here to enable the kernel to panic on "soft lockups",
1085 which are bugs that cause the kerne 1085 which are bugs that cause the kernel to loop in kernel
1086 mode for more than 20 seconds (conf 1086 mode for more than 20 seconds (configurable using the watchdog_thresh
1087 sysctl), without giving other tasks 1087 sysctl), without giving other tasks a chance to run.
1088 1088
1089 The panic can be used in combinatio 1089 The panic can be used in combination with panic_timeout,
1090 to cause the system to reboot autom 1090 to cause the system to reboot automatically after a
1091 lockup has been detected. This feat 1091 lockup has been detected. This feature is useful for
1092 high-availability systems that have 1092 high-availability systems that have uptime guarantees and
1093 where a lockup must be resolved ASA 1093 where a lockup must be resolved ASAP.
1094 1094
1095 Say N if unsure. 1095 Say N if unsure.
1096 1096
1097 config HAVE_HARDLOCKUP_DETECTOR_BUDDY 1097 config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1098 bool 1098 bool
1099 depends on SMP 1099 depends on SMP
1100 default y 1100 default y
1101 1101
1102 # 1102 #
1103 # Global switch whether to build a hardlockup 1103 # Global switch whether to build a hardlockup detector at all. It is available
1104 # only when the architecture supports at leas 1104 # only when the architecture supports at least one implementation. There are
1105 # two exceptions. The hardlockup detector is 1105 # two exceptions. The hardlockup detector is never enabled on:
1106 # 1106 #
1107 # s390: it reported many false positive 1107 # s390: it reported many false positives there
1108 # 1108 #
1109 # sparc64: has a custom implementation 1109 # sparc64: has a custom implementation which is not using the common
1110 # hardlockup command line optio 1110 # hardlockup command line options and sysctl interface.
1111 # 1111 #
1112 config HARDLOCKUP_DETECTOR 1112 config HARDLOCKUP_DETECTOR
1113 bool "Detect Hard Lockups" 1113 bool "Detect Hard Lockups"
1114 depends on DEBUG_KERNEL && !S390 && ! 1114 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1115 depends on HAVE_HARDLOCKUP_DETECTOR_P 1115 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1116 imply HARDLOCKUP_DETECTOR_PERF 1116 imply HARDLOCKUP_DETECTOR_PERF
1117 imply HARDLOCKUP_DETECTOR_BUDDY 1117 imply HARDLOCKUP_DETECTOR_BUDDY
1118 imply HARDLOCKUP_DETECTOR_ARCH 1118 imply HARDLOCKUP_DETECTOR_ARCH
1119 select LOCKUP_DETECTOR 1119 select LOCKUP_DETECTOR
1120 1120
1121 help 1121 help
1122 Say Y here to enable the kernel to 1122 Say Y here to enable the kernel to act as a watchdog to detect
1123 hard lockups. 1123 hard lockups.
1124 1124
1125 Hardlockups are bugs that cause the 1125 Hardlockups are bugs that cause the CPU to loop in kernel mode
1126 for more than 10 seconds, without l 1126 for more than 10 seconds, without letting other interrupts have a
1127 chance to run. The current stack t 1127 chance to run. The current stack trace is displayed upon detection
1128 and the system will stay locked up. 1128 and the system will stay locked up.
1129 1129
1130 # 1130 #
1131 # Note that arch-specific variants are always 1131 # Note that arch-specific variants are always preferred.
1132 # 1132 #
1133 config HARDLOCKUP_DETECTOR_PREFER_BUDDY 1133 config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1134 bool "Prefer the buddy CPU hardlockup 1134 bool "Prefer the buddy CPU hardlockup detector"
1135 depends on HARDLOCKUP_DETECTOR 1135 depends on HARDLOCKUP_DETECTOR
1136 depends on HAVE_HARDLOCKUP_DETECTOR_P 1136 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1137 depends on !HAVE_HARDLOCKUP_DETECTOR_ 1137 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1138 help 1138 help
1139 Say Y here to prefer the buddy hard 1139 Say Y here to prefer the buddy hardlockup detector over the perf one.
1140 1140
1141 With the buddy detector, each CPU u 1141 With the buddy detector, each CPU uses its softlockup hrtimer
1142 to check that the next CPU is proce 1142 to check that the next CPU is processing hrtimer interrupts by
1143 verifying that a counter is increas 1143 verifying that a counter is increasing.
1144 1144
1145 This hardlockup detector is useful 1145 This hardlockup detector is useful on systems that don't have
1146 an arch-specific hardlockup detecto 1146 an arch-specific hardlockup detector or if resources needed
1147 for the hardlockup detector are bet 1147 for the hardlockup detector are better used for other things.
1148 1148
1149 config HARDLOCKUP_DETECTOR_PERF 1149 config HARDLOCKUP_DETECTOR_PERF
1150 bool 1150 bool
1151 depends on HARDLOCKUP_DETECTOR 1151 depends on HARDLOCKUP_DETECTOR
1152 depends on HAVE_HARDLOCKUP_DETECTOR_P 1152 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1153 depends on !HAVE_HARDLOCKUP_DETECTOR_ 1153 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1154 select HARDLOCKUP_DETECTOR_COUNTS_HRT 1154 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1155 1155
1156 config HARDLOCKUP_DETECTOR_BUDDY 1156 config HARDLOCKUP_DETECTOR_BUDDY
1157 bool 1157 bool
1158 depends on HARDLOCKUP_DETECTOR 1158 depends on HARDLOCKUP_DETECTOR
1159 depends on HAVE_HARDLOCKUP_DETECTOR_B 1159 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1160 depends on !HAVE_HARDLOCKUP_DETECTOR_ 1160 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1161 depends on !HAVE_HARDLOCKUP_DETECTOR_ 1161 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1162 select HARDLOCKUP_DETECTOR_COUNTS_HRT 1162 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1163 1163
1164 config HARDLOCKUP_DETECTOR_ARCH 1164 config HARDLOCKUP_DETECTOR_ARCH
1165 bool 1165 bool
1166 depends on HARDLOCKUP_DETECTOR 1166 depends on HARDLOCKUP_DETECTOR
1167 depends on HAVE_HARDLOCKUP_DETECTOR_A 1167 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1168 help 1168 help
1169 The arch-specific implementation of 1169 The arch-specific implementation of the hardlockup detector will
1170 be used. 1170 be used.
1171 1171
1172 # 1172 #
1173 # Both the "perf" and "buddy" hardlockup dete 1173 # Both the "perf" and "buddy" hardlockup detectors count hrtimer
1174 # interrupts. This config enables functions m 1174 # interrupts. This config enables functions managing this common code.
1175 # 1175 #
1176 config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1176 config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1177 bool 1177 bool
1178 select SOFTLOCKUP_DETECTOR 1178 select SOFTLOCKUP_DETECTOR
1179 1179
1180 # 1180 #
1181 # Enables a timestamp based low pass filter t 1181 # Enables a timestamp based low pass filter to compensate for perf based
1182 # hard lockup detection which runs too fast d 1182 # hard lockup detection which runs too fast due to turbo modes.
1183 # 1183 #
1184 config HARDLOCKUP_CHECK_TIMESTAMP 1184 config HARDLOCKUP_CHECK_TIMESTAMP
1185 bool 1185 bool
1186 1186
1187 config BOOTPARAM_HARDLOCKUP_PANIC 1187 config BOOTPARAM_HARDLOCKUP_PANIC
1188 bool "Panic (Reboot) On Hard Lockups" 1188 bool "Panic (Reboot) On Hard Lockups"
1189 depends on HARDLOCKUP_DETECTOR 1189 depends on HARDLOCKUP_DETECTOR
1190 help 1190 help
1191 Say Y here to enable the kernel to 1191 Say Y here to enable the kernel to panic on "hard lockups",
1192 which are bugs that cause the kerne 1192 which are bugs that cause the kernel to loop in kernel
1193 mode with interrupts disabled for m 1193 mode with interrupts disabled for more than 10 seconds (configurable
1194 using the watchdog_thresh sysctl). 1194 using the watchdog_thresh sysctl).
1195 1195
1196 Say N if unsure. 1196 Say N if unsure.
1197 1197
1198 config DETECT_HUNG_TASK 1198 config DETECT_HUNG_TASK
1199 bool "Detect Hung Tasks" 1199 bool "Detect Hung Tasks"
1200 depends on DEBUG_KERNEL 1200 depends on DEBUG_KERNEL
1201 default SOFTLOCKUP_DETECTOR 1201 default SOFTLOCKUP_DETECTOR
1202 help 1202 help
1203 Say Y here to enable the kernel to 1203 Say Y here to enable the kernel to detect "hung tasks",
1204 which are bugs that cause the task 1204 which are bugs that cause the task to be stuck in
1205 uninterruptible "D" state indefinit 1205 uninterruptible "D" state indefinitely.
1206 1206
1207 When a hung task is detected, the k 1207 When a hung task is detected, the kernel will print the
1208 current stack trace (which you shou 1208 current stack trace (which you should report), but the
1209 task will stay in uninterruptible s 1209 task will stay in uninterruptible state. If lockdep is
1210 enabled then all held locks will al 1210 enabled then all held locks will also be reported. This
1211 feature has negligible overhead. 1211 feature has negligible overhead.
1212 1212
1213 config DEFAULT_HUNG_TASK_TIMEOUT 1213 config DEFAULT_HUNG_TASK_TIMEOUT
1214 int "Default timeout for hung task de 1214 int "Default timeout for hung task detection (in seconds)"
1215 depends on DETECT_HUNG_TASK 1215 depends on DETECT_HUNG_TASK
1216 default 120 1216 default 120
1217 help 1217 help
1218 This option controls the default ti 1218 This option controls the default timeout (in seconds) used
1219 to determine when a task has become 1219 to determine when a task has become non-responsive and should
1220 be considered hung. 1220 be considered hung.
1221 1221
1222 It can be adjusted at runtime via t 1222 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1223 sysctl or by writing a value to 1223 sysctl or by writing a value to
1224 /proc/sys/kernel/hung_task_timeout_ 1224 /proc/sys/kernel/hung_task_timeout_secs.
1225 1225
1226 A timeout of 0 disables the check. 1226 A timeout of 0 disables the check. The default is two minutes.
1227 Keeping the default should be fine 1227 Keeping the default should be fine in most cases.
1228 1228
1229 config BOOTPARAM_HUNG_TASK_PANIC 1229 config BOOTPARAM_HUNG_TASK_PANIC
1230 bool "Panic (Reboot) On Hung Tasks" 1230 bool "Panic (Reboot) On Hung Tasks"
1231 depends on DETECT_HUNG_TASK 1231 depends on DETECT_HUNG_TASK
1232 help 1232 help
1233 Say Y here to enable the kernel to 1233 Say Y here to enable the kernel to panic on "hung tasks",
1234 which are bugs that cause the kerne 1234 which are bugs that cause the kernel to leave a task stuck
1235 in uninterruptible "D" state. 1235 in uninterruptible "D" state.
1236 1236
1237 The panic can be used in combinatio 1237 The panic can be used in combination with panic_timeout,
1238 to cause the system to reboot autom 1238 to cause the system to reboot automatically after a
1239 hung task has been detected. This f 1239 hung task has been detected. This feature is useful for
1240 high-availability systems that have 1240 high-availability systems that have uptime guarantees and
1241 where a hung tasks must be resolved 1241 where a hung tasks must be resolved ASAP.
1242 1242
1243 Say N if unsure. 1243 Say N if unsure.
1244 1244
1245 config WQ_WATCHDOG 1245 config WQ_WATCHDOG
1246 bool "Detect Workqueue Stalls" 1246 bool "Detect Workqueue Stalls"
1247 depends on DEBUG_KERNEL 1247 depends on DEBUG_KERNEL
1248 help 1248 help
1249 Say Y here to enable stall detectio 1249 Say Y here to enable stall detection on workqueues. If a
1250 worker pool doesn't make forward pr 1250 worker pool doesn't make forward progress on a pending work
1251 item for over a given amount of tim 1251 item for over a given amount of time, 30s by default, a
1252 warning message is printed along wi 1252 warning message is printed along with dump of workqueue
1253 state. This can be configured thro 1253 state. This can be configured through kernel parameter
1254 "workqueue.watchdog_thresh" and its 1254 "workqueue.watchdog_thresh" and its sysfs counterpart.
1255 1255
1256 config WQ_CPU_INTENSIVE_REPORT 1256 config WQ_CPU_INTENSIVE_REPORT
1257 bool "Report per-cpu work items which 1257 bool "Report per-cpu work items which hog CPU for too long"
1258 depends on DEBUG_KERNEL 1258 depends on DEBUG_KERNEL
1259 help 1259 help
1260 Say Y here to enable reporting of c 1260 Say Y here to enable reporting of concurrency-managed per-cpu work
1261 items that hog CPUs for longer than 1261 items that hog CPUs for longer than
1262 workqueue.cpu_intensive_thresh_us. 1262 workqueue.cpu_intensive_thresh_us. Workqueue automatically
1263 detects and excludes them from conc 1263 detects and excludes them from concurrency management to prevent
1264 them from stalling other per-cpu wo 1264 them from stalling other per-cpu work items. Occassional
1265 triggering may not necessarily indi 1265 triggering may not necessarily indicate a problem. Repeated
1266 triggering likely indicates that th 1266 triggering likely indicates that the work item should be switched
1267 to use an unbound workqueue. 1267 to use an unbound workqueue.
1268 1268
1269 config TEST_LOCKUP 1269 config TEST_LOCKUP
1270 tristate "Test module to generate loc 1270 tristate "Test module to generate lockups"
1271 depends on m 1271 depends on m
1272 help 1272 help
1273 This builds the "test_lockup" modul 1273 This builds the "test_lockup" module that helps to make sure
1274 that watchdogs and lockup detectors 1274 that watchdogs and lockup detectors are working properly.
1275 1275
1276 Depending on module parameters it c 1276 Depending on module parameters it could emulate soft or hard
1277 lockup, "hung task", or locking arb 1277 lockup, "hung task", or locking arbitrary lock for a long time.
1278 Also it could generate series of lo 1278 Also it could generate series of lockups with cooling-down periods.
1279 1279
1280 If unsure, say N. 1280 If unsure, say N.
1281 1281
1282 endmenu # "Debug lockups and hangs" 1282 endmenu # "Debug lockups and hangs"
1283 1283
1284 menu "Scheduler Debugging" 1284 menu "Scheduler Debugging"
1285 1285
1286 config SCHED_DEBUG 1286 config SCHED_DEBUG
1287 bool "Collect scheduler debugging inf 1287 bool "Collect scheduler debugging info"
1288 depends on DEBUG_KERNEL && DEBUG_FS 1288 depends on DEBUG_KERNEL && DEBUG_FS
1289 default y 1289 default y
1290 help 1290 help
1291 If you say Y here, the /sys/kernel/ 1291 If you say Y here, the /sys/kernel/debug/sched file will be provided
1292 that can help debug the scheduler. 1292 that can help debug the scheduler. The runtime overhead of this
1293 option is minimal. 1293 option is minimal.
1294 1294
1295 config SCHED_INFO 1295 config SCHED_INFO
1296 bool 1296 bool
1297 default n 1297 default n
1298 1298
1299 config SCHEDSTATS 1299 config SCHEDSTATS
1300 bool "Collect scheduler statistics" 1300 bool "Collect scheduler statistics"
1301 depends on PROC_FS 1301 depends on PROC_FS
1302 select SCHED_INFO 1302 select SCHED_INFO
1303 help 1303 help
1304 If you say Y here, additional code 1304 If you say Y here, additional code will be inserted into the
1305 scheduler and related routines to c 1305 scheduler and related routines to collect statistics about
1306 scheduler behavior and provide them 1306 scheduler behavior and provide them in /proc/schedstat. These
1307 stats may be useful for both tuning 1307 stats may be useful for both tuning and debugging the scheduler
1308 If you aren't debugging the schedul 1308 If you aren't debugging the scheduler or trying to tune a specific
1309 application, you can say N to avoid 1309 application, you can say N to avoid the very slight overhead
1310 this adds. 1310 this adds.
1311 1311
1312 endmenu 1312 endmenu
1313 1313
1314 config DEBUG_TIMEKEEPING 1314 config DEBUG_TIMEKEEPING
1315 bool "Enable extra timekeeping sanity 1315 bool "Enable extra timekeeping sanity checking"
1316 help 1316 help
1317 This option will enable additional 1317 This option will enable additional timekeeping sanity checks
1318 which may be helpful when diagnosin 1318 which may be helpful when diagnosing issues where timekeeping
1319 problems are suspected. 1319 problems are suspected.
1320 1320
1321 This may include checks in the time 1321 This may include checks in the timekeeping hotpaths, so this
1322 option may have a (very small) perf 1322 option may have a (very small) performance impact to some
1323 workloads. 1323 workloads.
1324 1324
1325 If unsure, say N. 1325 If unsure, say N.
1326 1326
1327 config DEBUG_PREEMPT 1327 config DEBUG_PREEMPT
1328 bool "Debug preemptible kernel" 1328 bool "Debug preemptible kernel"
1329 depends on DEBUG_KERNEL && PREEMPTION 1329 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1330 help 1330 help
1331 If you say Y here then the kernel w 1331 If you say Y here then the kernel will use a debug variant of the
1332 commonly used smp_processor_id() fu 1332 commonly used smp_processor_id() function and will print warnings
1333 if kernel code uses it in a preempt 1333 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1334 will detect preemption count underf 1334 will detect preemption count underflows.
1335 1335
1336 This option has potential to introd 1336 This option has potential to introduce high runtime overhead,
1337 depending on workload as it trigger 1337 depending on workload as it triggers debugging routines for each
1338 this_cpu operation. It should only 1338 this_cpu operation. It should only be used for debugging purposes.
1339 1339
1340 menu "Lock Debugging (spinlocks, mutexes, etc 1340 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1341 1341
1342 config LOCK_DEBUGGING_SUPPORT 1342 config LOCK_DEBUGGING_SUPPORT
1343 bool 1343 bool
1344 depends on TRACE_IRQFLAGS_SUPPORT && 1344 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1345 default y 1345 default y
1346 1346
1347 config PROVE_LOCKING 1347 config PROVE_LOCKING
1348 bool "Lock debugging: prove locking c 1348 bool "Lock debugging: prove locking correctness"
1349 depends on DEBUG_KERNEL && LOCK_DEBUG 1349 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1350 select LOCKDEP 1350 select LOCKDEP
1351 select DEBUG_SPINLOCK 1351 select DEBUG_SPINLOCK
1352 select DEBUG_MUTEXES if !PREEMPT_RT 1352 select DEBUG_MUTEXES if !PREEMPT_RT
1353 select DEBUG_RT_MUTEXES if RT_MUTEXES 1353 select DEBUG_RT_MUTEXES if RT_MUTEXES
1354 select DEBUG_RWSEMS if !PREEMPT_RT 1354 select DEBUG_RWSEMS if !PREEMPT_RT
1355 select DEBUG_WW_MUTEX_SLOWPATH 1355 select DEBUG_WW_MUTEX_SLOWPATH
1356 select DEBUG_LOCK_ALLOC 1356 select DEBUG_LOCK_ALLOC
1357 select PREEMPT_COUNT if !ARCH_NO_PREE 1357 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1358 select TRACE_IRQFLAGS 1358 select TRACE_IRQFLAGS
1359 default n 1359 default n
1360 help 1360 help
1361 This feature enables the kernel to p 1361 This feature enables the kernel to prove that all locking
1362 that occurs in the kernel runtime is 1362 that occurs in the kernel runtime is mathematically
1363 correct: that under no circumstance 1363 correct: that under no circumstance could an arbitrary (and
1364 not yet triggered) combination of ob 1364 not yet triggered) combination of observed locking
1365 sequences (on an arbitrary number of 1365 sequences (on an arbitrary number of CPUs, running an
1366 arbitrary number of tasks and interr 1366 arbitrary number of tasks and interrupt contexts) cause a
1367 deadlock. 1367 deadlock.
1368 1368
1369 In short, this feature enables the k 1369 In short, this feature enables the kernel to report locking
1370 related deadlocks before they actual 1370 related deadlocks before they actually occur.
1371 1371
1372 The proof does not depend on how har 1372 The proof does not depend on how hard and complex a
1373 deadlock scenario would be to trigge 1373 deadlock scenario would be to trigger: how many
1374 participant CPUs, tasks and irq-cont 1374 participant CPUs, tasks and irq-contexts would be needed
1375 for it to trigger. The proof also do 1375 for it to trigger. The proof also does not depend on
1376 timing: if a race and a resulting de 1376 timing: if a race and a resulting deadlock is possible
1377 theoretically (no matter how unlikel 1377 theoretically (no matter how unlikely the race scenario
1378 is), it will be proven so and will i 1378 is), it will be proven so and will immediately be
1379 reported by the kernel (once the eve 1379 reported by the kernel (once the event is observed that
1380 makes the deadlock theoretically pos 1380 makes the deadlock theoretically possible).
1381 1381
1382 If a deadlock is impossible (i.e. th 1382 If a deadlock is impossible (i.e. the locking rules, as
1383 observed by the kernel, are mathemat 1383 observed by the kernel, are mathematically correct), the
1384 kernel reports nothing. 1384 kernel reports nothing.
1385 1385
1386 NOTE: this feature can also be enabl 1386 NOTE: this feature can also be enabled for rwlocks, mutexes
1387 and rwsems - in which case all depen 1387 and rwsems - in which case all dependencies between these
1388 different locking variants are obser 1388 different locking variants are observed and mapped too, and
1389 the proof of observed correctness is 1389 the proof of observed correctness is also maintained for an
1390 arbitrary combination of these separ 1390 arbitrary combination of these separate locking variants.
1391 1391
1392 For more details, see Documentation/ 1392 For more details, see Documentation/locking/lockdep-design.rst.
1393 1393
1394 config PROVE_RAW_LOCK_NESTING 1394 config PROVE_RAW_LOCK_NESTING
1395 bool "Enable raw_spinlock - spinlock 1395 bool "Enable raw_spinlock - spinlock nesting checks"
1396 depends on PROVE_LOCKING 1396 depends on PROVE_LOCKING
1397 default n 1397 default n
1398 help 1398 help
1399 Enable the raw_spinlock vs. spinlock 1399 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1400 that the lock nesting rules for PREE 1400 that the lock nesting rules for PREEMPT_RT enabled kernels are
1401 not violated. 1401 not violated.
1402 1402
1403 NOTE: There are known nesting proble 1403 NOTE: There are known nesting problems. So if you enable this
1404 option expect lockdep splats until t 1404 option expect lockdep splats until these problems have been fully
1405 addressed which is work in progress. 1405 addressed which is work in progress. This config switch allows to
1406 identify and analyze these problems. 1406 identify and analyze these problems. It will be removed and the
1407 check permanently enabled once the m 1407 check permanently enabled once the main issues have been fixed.
1408 1408
1409 If unsure, select N. 1409 If unsure, select N.
1410 1410
1411 config LOCK_STAT 1411 config LOCK_STAT
1412 bool "Lock usage statistics" 1412 bool "Lock usage statistics"
1413 depends on DEBUG_KERNEL && LOCK_DEBUG 1413 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1414 select LOCKDEP 1414 select LOCKDEP
1415 select DEBUG_SPINLOCK 1415 select DEBUG_SPINLOCK
1416 select DEBUG_MUTEXES if !PREEMPT_RT 1416 select DEBUG_MUTEXES if !PREEMPT_RT
1417 select DEBUG_RT_MUTEXES if RT_MUTEXES 1417 select DEBUG_RT_MUTEXES if RT_MUTEXES
1418 select DEBUG_LOCK_ALLOC 1418 select DEBUG_LOCK_ALLOC
1419 default n 1419 default n
1420 help 1420 help
1421 This feature enables tracking lock c 1421 This feature enables tracking lock contention points
1422 1422
1423 For more details, see Documentation/ 1423 For more details, see Documentation/locking/lockstat.rst
1424 1424
1425 This also enables lock events requir 1425 This also enables lock events required by "perf lock",
1426 subcommand of perf. 1426 subcommand of perf.
1427 If you want to use "perf lock", you 1427 If you want to use "perf lock", you also need to turn on
1428 CONFIG_EVENT_TRACING. 1428 CONFIG_EVENT_TRACING.
1429 1429
1430 CONFIG_LOCK_STAT defines "contended" 1430 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1431 (CONFIG_LOCKDEP defines "acquire" an 1431 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1432 1432
1433 config DEBUG_RT_MUTEXES 1433 config DEBUG_RT_MUTEXES
1434 bool "RT Mutex debugging, deadlock de 1434 bool "RT Mutex debugging, deadlock detection"
1435 depends on DEBUG_KERNEL && RT_MUTEXES 1435 depends on DEBUG_KERNEL && RT_MUTEXES
1436 help 1436 help
1437 This allows rt mutex semantics viola 1437 This allows rt mutex semantics violations and rt mutex related
1438 deadlocks (lockups) to be detected a 1438 deadlocks (lockups) to be detected and reported automatically.
1439 1439
1440 config DEBUG_SPINLOCK 1440 config DEBUG_SPINLOCK
1441 bool "Spinlock and rw-lock debugging: 1441 bool "Spinlock and rw-lock debugging: basic checks"
1442 depends on DEBUG_KERNEL 1442 depends on DEBUG_KERNEL
1443 select UNINLINE_SPIN_UNLOCK 1443 select UNINLINE_SPIN_UNLOCK
1444 help 1444 help
1445 Say Y here and build SMP to catch m 1445 Say Y here and build SMP to catch missing spinlock initialization
1446 and certain other kinds of spinlock 1446 and certain other kinds of spinlock errors commonly made. This is
1447 best used in conjunction with the N 1447 best used in conjunction with the NMI watchdog so that spinlock
1448 deadlocks are also debuggable. 1448 deadlocks are also debuggable.
1449 1449
1450 config DEBUG_MUTEXES 1450 config DEBUG_MUTEXES
1451 bool "Mutex debugging: basic checks" 1451 bool "Mutex debugging: basic checks"
1452 depends on DEBUG_KERNEL && !PREEMPT_R 1452 depends on DEBUG_KERNEL && !PREEMPT_RT
1453 help 1453 help
1454 This feature allows mutex semantics 1454 This feature allows mutex semantics violations to be detected and
1455 reported. 1455 reported.
1456 1456
1457 config DEBUG_WW_MUTEX_SLOWPATH 1457 config DEBUG_WW_MUTEX_SLOWPATH
1458 bool "Wait/wound mutex debugging: Slo 1458 bool "Wait/wound mutex debugging: Slowpath testing"
1459 depends on DEBUG_KERNEL && LOCK_DEBUG 1459 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1460 select DEBUG_LOCK_ALLOC 1460 select DEBUG_LOCK_ALLOC
1461 select DEBUG_SPINLOCK 1461 select DEBUG_SPINLOCK
1462 select DEBUG_MUTEXES if !PREEMPT_RT 1462 select DEBUG_MUTEXES if !PREEMPT_RT
1463 select DEBUG_RT_MUTEXES if PREEMPT_RT 1463 select DEBUG_RT_MUTEXES if PREEMPT_RT
1464 help 1464 help
1465 This feature enables slowpath testin 1465 This feature enables slowpath testing for w/w mutex users by
1466 injecting additional -EDEADLK wound/ 1466 injecting additional -EDEADLK wound/backoff cases. Together with
1467 the full mutex checks enabled with ( 1467 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1468 will test all possible w/w mutex int 1468 will test all possible w/w mutex interface abuse with the
1469 exception of simply not acquiring al 1469 exception of simply not acquiring all the required locks.
1470 Note that this feature can introduce 1470 Note that this feature can introduce significant overhead, so
1471 it really should not be enabled in a 1471 it really should not be enabled in a production or distro kernel,
1472 even a debug kernel. If you are a d 1472 even a debug kernel. If you are a driver writer, enable it. If
1473 you are a distro, do not. 1473 you are a distro, do not.
1474 1474
1475 config DEBUG_RWSEMS 1475 config DEBUG_RWSEMS
1476 bool "RW Semaphore debugging: basic c 1476 bool "RW Semaphore debugging: basic checks"
1477 depends on DEBUG_KERNEL && !PREEMPT_R 1477 depends on DEBUG_KERNEL && !PREEMPT_RT
1478 help 1478 help
1479 This debugging feature allows misma 1479 This debugging feature allows mismatched rw semaphore locks
1480 and unlocks to be detected and repo 1480 and unlocks to be detected and reported.
1481 1481
1482 config DEBUG_LOCK_ALLOC 1482 config DEBUG_LOCK_ALLOC
1483 bool "Lock debugging: detect incorrec 1483 bool "Lock debugging: detect incorrect freeing of live locks"
1484 depends on DEBUG_KERNEL && LOCK_DEBUG 1484 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1485 select DEBUG_SPINLOCK 1485 select DEBUG_SPINLOCK
1486 select DEBUG_MUTEXES if !PREEMPT_RT 1486 select DEBUG_MUTEXES if !PREEMPT_RT
1487 select DEBUG_RT_MUTEXES if RT_MUTEXES 1487 select DEBUG_RT_MUTEXES if RT_MUTEXES
1488 select LOCKDEP 1488 select LOCKDEP
1489 help 1489 help
1490 This feature will check whether any 1490 This feature will check whether any held lock (spinlock, rwlock,
1491 mutex or rwsem) is incorrectly freed 1491 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1492 memory-freeing routines (kfree(), km 1492 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1493 vfree(), etc.), whether a live lock 1493 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1494 spin_lock_init()/mutex_init()/etc., 1494 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1495 held during task exit. 1495 held during task exit.
1496 1496
1497 config LOCKDEP 1497 config LOCKDEP
1498 bool 1498 bool
1499 depends on DEBUG_KERNEL && LOCK_DEBUG 1499 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1500 select STACKTRACE 1500 select STACKTRACE
1501 select KALLSYMS 1501 select KALLSYMS
1502 select KALLSYMS_ALL 1502 select KALLSYMS_ALL
1503 1503
1504 config LOCKDEP_SMALL 1504 config LOCKDEP_SMALL
1505 bool 1505 bool
1506 1506
1507 config LOCKDEP_BITS 1507 config LOCKDEP_BITS
1508 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1508 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1509 depends on LOCKDEP && !LOCKDEP_SMALL 1509 depends on LOCKDEP && !LOCKDEP_SMALL
1510 range 10 30 1510 range 10 30
1511 default 15 1511 default 15
1512 help 1512 help
1513 Try increasing this value if you hi 1513 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1514 1514
1515 config LOCKDEP_CHAINS_BITS 1515 config LOCKDEP_CHAINS_BITS
1516 int "Bitsize for MAX_LOCKDEP_CHAINS" 1516 int "Bitsize for MAX_LOCKDEP_CHAINS"
1517 depends on LOCKDEP && !LOCKDEP_SMALL 1517 depends on LOCKDEP && !LOCKDEP_SMALL
1518 range 10 30 1518 range 10 30
1519 default 16 1519 default 16
1520 help 1520 help
1521 Try increasing this value if you hi 1521 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1522 1522
1523 config LOCKDEP_STACK_TRACE_BITS 1523 config LOCKDEP_STACK_TRACE_BITS
1524 int "Bitsize for MAX_STACK_TRACE_ENTR 1524 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1525 depends on LOCKDEP && !LOCKDEP_SMALL 1525 depends on LOCKDEP && !LOCKDEP_SMALL
1526 range 10 30 1526 range 10 30
1527 default 19 1527 default 19
1528 help 1528 help
1529 Try increasing this value if you hi 1529 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1530 1530
1531 config LOCKDEP_STACK_TRACE_HASH_BITS 1531 config LOCKDEP_STACK_TRACE_HASH_BITS
1532 int "Bitsize for STACK_TRACE_HASH_SIZ 1532 int "Bitsize for STACK_TRACE_HASH_SIZE"
1533 depends on LOCKDEP && !LOCKDEP_SMALL 1533 depends on LOCKDEP && !LOCKDEP_SMALL
1534 range 10 30 1534 range 10 30
1535 default 14 1535 default 14
1536 help 1536 help
1537 Try increasing this value if you ne 1537 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1538 1538
1539 config LOCKDEP_CIRCULAR_QUEUE_BITS 1539 config LOCKDEP_CIRCULAR_QUEUE_BITS
1540 int "Bitsize for elements in circular 1540 int "Bitsize for elements in circular_queue struct"
1541 depends on LOCKDEP 1541 depends on LOCKDEP
1542 range 10 30 1542 range 10 30
1543 default 12 1543 default 12
1544 help 1544 help
1545 Try increasing this value if you hi 1545 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1546 1546
1547 config DEBUG_LOCKDEP 1547 config DEBUG_LOCKDEP
1548 bool "Lock dependency engine debuggin 1548 bool "Lock dependency engine debugging"
1549 depends on DEBUG_KERNEL && LOCKDEP 1549 depends on DEBUG_KERNEL && LOCKDEP
1550 select DEBUG_IRQFLAGS 1550 select DEBUG_IRQFLAGS
1551 help 1551 help
1552 If you say Y here, the lock depende 1552 If you say Y here, the lock dependency engine will do
1553 additional runtime checks to debug 1553 additional runtime checks to debug itself, at the price
1554 of more runtime overhead. 1554 of more runtime overhead.
1555 1555
1556 config DEBUG_ATOMIC_SLEEP 1556 config DEBUG_ATOMIC_SLEEP
1557 bool "Sleep inside atomic section che 1557 bool "Sleep inside atomic section checking"
1558 select PREEMPT_COUNT 1558 select PREEMPT_COUNT
1559 depends on DEBUG_KERNEL 1559 depends on DEBUG_KERNEL
1560 depends on !ARCH_NO_PREEMPT 1560 depends on !ARCH_NO_PREEMPT
1561 help 1561 help
1562 If you say Y here, various routines 1562 If you say Y here, various routines which may sleep will become very
1563 noisy if they are called inside ato 1563 noisy if they are called inside atomic sections: when a spinlock is
1564 held, inside an rcu read side criti 1564 held, inside an rcu read side critical section, inside preempt disabled
1565 sections, inside an interrupt, etc. 1565 sections, inside an interrupt, etc...
1566 1566
1567 config DEBUG_LOCKING_API_SELFTESTS 1567 config DEBUG_LOCKING_API_SELFTESTS
1568 bool "Locking API boot-time self-test 1568 bool "Locking API boot-time self-tests"
1569 depends on DEBUG_KERNEL 1569 depends on DEBUG_KERNEL
1570 help 1570 help
1571 Say Y here if you want the kernel t 1571 Say Y here if you want the kernel to run a short self-test during
1572 bootup. The self-test checks whethe 1572 bootup. The self-test checks whether common types of locking bugs
1573 are detected by debugging mechanism 1573 are detected by debugging mechanisms or not. (if you disable
1574 lock debugging then those bugs won' 1574 lock debugging then those bugs won't be detected of course.)
1575 The following locking APIs are cove 1575 The following locking APIs are covered: spinlocks, rwlocks,
1576 mutexes and rwsems. 1576 mutexes and rwsems.
1577 1577
1578 config LOCK_TORTURE_TEST 1578 config LOCK_TORTURE_TEST
1579 tristate "torture tests for locking" 1579 tristate "torture tests for locking"
1580 depends on DEBUG_KERNEL 1580 depends on DEBUG_KERNEL
1581 select TORTURE_TEST 1581 select TORTURE_TEST
1582 help 1582 help
1583 This option provides a kernel modul 1583 This option provides a kernel module that runs torture tests
1584 on kernel locking primitives. The 1584 on kernel locking primitives. The kernel module may be built
1585 after the fact on the running kerne 1585 after the fact on the running kernel to be tested, if desired.
1586 1586
1587 Say Y here if you want kernel locki 1587 Say Y here if you want kernel locking-primitive torture tests
1588 to be built into the kernel. 1588 to be built into the kernel.
1589 Say M if you want these torture tes 1589 Say M if you want these torture tests to build as a module.
1590 Say N if you are unsure. 1590 Say N if you are unsure.
1591 1591
1592 config WW_MUTEX_SELFTEST 1592 config WW_MUTEX_SELFTEST
1593 tristate "Wait/wound mutex selftests" 1593 tristate "Wait/wound mutex selftests"
1594 help 1594 help
1595 This option provides a kernel modul 1595 This option provides a kernel module that runs tests on the
1596 on the struct ww_mutex locking API. 1596 on the struct ww_mutex locking API.
1597 1597
1598 It is recommended to enable DEBUG_W 1598 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1599 with this test harness. 1599 with this test harness.
1600 1600
1601 Say M if you want these self tests 1601 Say M if you want these self tests to build as a module.
1602 Say N if you are unsure. 1602 Say N if you are unsure.
1603 1603
1604 config SCF_TORTURE_TEST 1604 config SCF_TORTURE_TEST
1605 tristate "torture tests for smp_call_ 1605 tristate "torture tests for smp_call_function*()"
1606 depends on DEBUG_KERNEL 1606 depends on DEBUG_KERNEL
1607 select TORTURE_TEST 1607 select TORTURE_TEST
1608 help 1608 help
1609 This option provides a kernel modul 1609 This option provides a kernel module that runs torture tests
1610 on the smp_call_function() family o 1610 on the smp_call_function() family of primitives. The kernel
1611 module may be built after the fact 1611 module may be built after the fact on the running kernel to
1612 be tested, if desired. 1612 be tested, if desired.
1613 1613
1614 config CSD_LOCK_WAIT_DEBUG 1614 config CSD_LOCK_WAIT_DEBUG
1615 bool "Debugging for csd_lock_wait(), 1615 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1616 depends on DEBUG_KERNEL 1616 depends on DEBUG_KERNEL
1617 depends on 64BIT 1617 depends on 64BIT
1618 default n 1618 default n
1619 help 1619 help
1620 This option enables debug prints wh 1620 This option enables debug prints when CPUs are slow to respond
1621 to the smp_call_function*() IPI wra 1621 to the smp_call_function*() IPI wrappers. These debug prints
1622 include the IPI handler function cu 1622 include the IPI handler function currently executing (if any)
1623 and relevant stack traces. 1623 and relevant stack traces.
1624 1624
1625 config CSD_LOCK_WAIT_DEBUG_DEFAULT 1625 config CSD_LOCK_WAIT_DEBUG_DEFAULT
1626 bool "Default csd_lock_wait() debuggi 1626 bool "Default csd_lock_wait() debugging on at boot time"
1627 depends on CSD_LOCK_WAIT_DEBUG 1627 depends on CSD_LOCK_WAIT_DEBUG
1628 depends on 64BIT 1628 depends on 64BIT
1629 default n 1629 default n
1630 help 1630 help
1631 This option causes the csdlock_debu 1631 This option causes the csdlock_debug= kernel boot parameter to
1632 default to 1 (basic debugging) inst 1632 default to 1 (basic debugging) instead of 0 (no debugging).
1633 1633
1634 endmenu # lock debugging 1634 endmenu # lock debugging
1635 1635
1636 config TRACE_IRQFLAGS 1636 config TRACE_IRQFLAGS
1637 depends on TRACE_IRQFLAGS_SUPPORT 1637 depends on TRACE_IRQFLAGS_SUPPORT
1638 bool 1638 bool
1639 help 1639 help
1640 Enables hooks to interrupt enabling 1640 Enables hooks to interrupt enabling and disabling for
1641 either tracing or lock debugging. 1641 either tracing or lock debugging.
1642 1642
1643 config TRACE_IRQFLAGS_NMI 1643 config TRACE_IRQFLAGS_NMI
1644 def_bool y 1644 def_bool y
1645 depends on TRACE_IRQFLAGS 1645 depends on TRACE_IRQFLAGS
1646 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1646 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1647 1647
1648 config NMI_CHECK_CPU 1648 config NMI_CHECK_CPU
1649 bool "Debugging for CPUs failing to r 1649 bool "Debugging for CPUs failing to respond to backtrace requests"
1650 depends on DEBUG_KERNEL 1650 depends on DEBUG_KERNEL
1651 depends on X86 1651 depends on X86
1652 default n 1652 default n
1653 help 1653 help
1654 Enables debug prints when a CPU fai 1654 Enables debug prints when a CPU fails to respond to a given
1655 backtrace NMI. These prints provid 1655 backtrace NMI. These prints provide some reasons why a CPU
1656 might legitimately be failing to re 1656 might legitimately be failing to respond, for example, if it
1657 is offline of if ignore_nmis is set 1657 is offline of if ignore_nmis is set.
1658 1658
1659 config DEBUG_IRQFLAGS 1659 config DEBUG_IRQFLAGS
1660 bool "Debug IRQ flag manipulation" 1660 bool "Debug IRQ flag manipulation"
1661 help 1661 help
1662 Enables checks for potentially unsa 1662 Enables checks for potentially unsafe enabling or disabling of
1663 interrupts, such as calling raw_loc 1663 interrupts, such as calling raw_local_irq_restore() when interrupts
1664 are enabled. 1664 are enabled.
1665 1665
1666 config STACKTRACE 1666 config STACKTRACE
1667 bool "Stack backtrace support" 1667 bool "Stack backtrace support"
1668 depends on STACKTRACE_SUPPORT 1668 depends on STACKTRACE_SUPPORT
1669 help 1669 help
1670 This option causes the kernel to cr 1670 This option causes the kernel to create a /proc/pid/stack for
1671 every process, showing its current 1671 every process, showing its current stack trace.
1672 It is also used by various kernel d 1672 It is also used by various kernel debugging features that require
1673 stack trace generation. 1673 stack trace generation.
1674 1674
1675 config WARN_ALL_UNSEEDED_RANDOM 1675 config WARN_ALL_UNSEEDED_RANDOM
1676 bool "Warn for all uses of unseeded r 1676 bool "Warn for all uses of unseeded randomness"
1677 default n 1677 default n
1678 help 1678 help
1679 Some parts of the kernel contain bu 1679 Some parts of the kernel contain bugs relating to their use of
1680 cryptographically secure random num 1680 cryptographically secure random numbers before it's actually possible
1681 to generate those numbers securely. 1681 to generate those numbers securely. This setting ensures that these
1682 flaws don't go unnoticed, by enabli 1682 flaws don't go unnoticed, by enabling a message, should this ever
1683 occur. This will allow people with 1683 occur. This will allow people with obscure setups to know when things
1684 are going wrong, so that they might 1684 are going wrong, so that they might contact developers about fixing
1685 it. 1685 it.
1686 1686
1687 Unfortunately, on some models of so 1687 Unfortunately, on some models of some architectures getting
1688 a fully seeded CRNG is extremely di 1688 a fully seeded CRNG is extremely difficult, and so this can
1689 result in dmesg getting spammed for 1689 result in dmesg getting spammed for a surprisingly long
1690 time. This is really bad from a se 1690 time. This is really bad from a security perspective, and
1691 so architecture maintainers really 1691 so architecture maintainers really need to do what they can
1692 to get the CRNG seeded sooner after 1692 to get the CRNG seeded sooner after the system is booted.
1693 However, since users cannot do anyt 1693 However, since users cannot do anything actionable to
1694 address this, by default this optio 1694 address this, by default this option is disabled.
1695 1695
1696 Say Y here if you want to receive w 1696 Say Y here if you want to receive warnings for all uses of
1697 unseeded randomness. This will be 1697 unseeded randomness. This will be of use primarily for
1698 those developers interested in impr 1698 those developers interested in improving the security of
1699 Linux kernels running on their arch 1699 Linux kernels running on their architecture (or
1700 subarchitecture). 1700 subarchitecture).
1701 1701
1702 config DEBUG_KOBJECT 1702 config DEBUG_KOBJECT
1703 bool "kobject debugging" 1703 bool "kobject debugging"
1704 depends on DEBUG_KERNEL 1704 depends on DEBUG_KERNEL
1705 help 1705 help
1706 If you say Y here, some extra kobje 1706 If you say Y here, some extra kobject debugging messages will be sent
1707 to the syslog. 1707 to the syslog.
1708 1708
1709 config DEBUG_KOBJECT_RELEASE 1709 config DEBUG_KOBJECT_RELEASE
1710 bool "kobject release debugging" 1710 bool "kobject release debugging"
1711 depends on DEBUG_OBJECTS_TIMERS 1711 depends on DEBUG_OBJECTS_TIMERS
1712 help 1712 help
1713 kobjects are reference counted obje 1713 kobjects are reference counted objects. This means that their
1714 last reference count put is not pre 1714 last reference count put is not predictable, and the kobject can
1715 live on past the point at which a d 1715 live on past the point at which a driver decides to drop its
1716 initial reference to the kobject ga 1716 initial reference to the kobject gained on allocation. An
1717 example of this would be a struct d 1717 example of this would be a struct device which has just been
1718 unregistered. 1718 unregistered.
1719 1719
1720 However, some buggy drivers assume 1720 However, some buggy drivers assume that after such an operation,
1721 the memory backing the kobject can 1721 the memory backing the kobject can be immediately freed. This
1722 goes completely against the princip 1722 goes completely against the principles of a refcounted object.
1723 1723
1724 If you say Y here, the kernel will 1724 If you say Y here, the kernel will delay the release of kobjects
1725 on the last reference count to impr 1725 on the last reference count to improve the visibility of this
1726 kind of kobject release bug. 1726 kind of kobject release bug.
1727 1727
1728 config HAVE_DEBUG_BUGVERBOSE 1728 config HAVE_DEBUG_BUGVERBOSE
1729 bool 1729 bool
1730 1730
1731 menu "Debug kernel data structures" 1731 menu "Debug kernel data structures"
1732 1732
1733 config DEBUG_LIST 1733 config DEBUG_LIST
1734 bool "Debug linked list manipulation" 1734 bool "Debug linked list manipulation"
1735 depends on DEBUG_KERNEL 1735 depends on DEBUG_KERNEL
1736 select LIST_HARDENED 1736 select LIST_HARDENED
1737 help 1737 help
1738 Enable this to turn on extended che 1738 Enable this to turn on extended checks in the linked-list walking
1739 routines. 1739 routines.
1740 1740
1741 This option trades better quality e 1741 This option trades better quality error reports for performance, and
1742 is more suitable for kernel debuggi 1742 is more suitable for kernel debugging. If you care about performance,
1743 you should only enable CONFIG_LIST_ 1743 you should only enable CONFIG_LIST_HARDENED instead.
1744 1744
1745 If unsure, say N. 1745 If unsure, say N.
1746 1746
1747 config DEBUG_PLIST 1747 config DEBUG_PLIST
1748 bool "Debug priority linked list mani 1748 bool "Debug priority linked list manipulation"
1749 depends on DEBUG_KERNEL 1749 depends on DEBUG_KERNEL
1750 help 1750 help
1751 Enable this to turn on extended che 1751 Enable this to turn on extended checks in the priority-ordered
1752 linked-list (plist) walking routine 1752 linked-list (plist) walking routines. This checks the entire
1753 list multiple times during each man 1753 list multiple times during each manipulation.
1754 1754
1755 If unsure, say N. 1755 If unsure, say N.
1756 1756
1757 config DEBUG_SG 1757 config DEBUG_SG
1758 bool "Debug SG table operations" 1758 bool "Debug SG table operations"
1759 depends on DEBUG_KERNEL 1759 depends on DEBUG_KERNEL
1760 help 1760 help
1761 Enable this to turn on checks on sc 1761 Enable this to turn on checks on scatter-gather tables. This can
1762 help find problems with drivers tha 1762 help find problems with drivers that do not properly initialize
1763 their sg tables. 1763 their sg tables.
1764 1764
1765 If unsure, say N. 1765 If unsure, say N.
1766 1766
1767 config DEBUG_NOTIFIERS 1767 config DEBUG_NOTIFIERS
1768 bool "Debug notifier call chains" 1768 bool "Debug notifier call chains"
1769 depends on DEBUG_KERNEL 1769 depends on DEBUG_KERNEL
1770 help 1770 help
1771 Enable this to turn on sanity check 1771 Enable this to turn on sanity checking for notifier call chains.
1772 This is most useful for kernel deve 1772 This is most useful for kernel developers to make sure that
1773 modules properly unregister themsel 1773 modules properly unregister themselves from notifier chains.
1774 This is a relatively cheap check bu 1774 This is a relatively cheap check but if you care about maximum
1775 performance, say N. 1775 performance, say N.
1776 1776
1777 config DEBUG_CLOSURES 1777 config DEBUG_CLOSURES
1778 bool "Debug closures (bcache async wi 1778 bool "Debug closures (bcache async widgits)"
1779 depends on CLOSURES 1779 depends on CLOSURES
1780 select DEBUG_FS 1780 select DEBUG_FS
1781 help 1781 help
1782 Keeps all active closures in a link 1782 Keeps all active closures in a linked list and provides a debugfs
1783 interface to list them, which makes 1783 interface to list them, which makes it possible to see asynchronous
1784 operations that get stuck. 1784 operations that get stuck.
1785 1785
1786 config DEBUG_MAPLE_TREE 1786 config DEBUG_MAPLE_TREE
1787 bool "Debug maple trees" 1787 bool "Debug maple trees"
1788 depends on DEBUG_KERNEL 1788 depends on DEBUG_KERNEL
1789 help 1789 help
1790 Enable maple tree debugging informa 1790 Enable maple tree debugging information and extra validations.
1791 1791
1792 If unsure, say N. 1792 If unsure, say N.
1793 1793
1794 endmenu 1794 endmenu
1795 1795
1796 source "kernel/rcu/Kconfig.debug" 1796 source "kernel/rcu/Kconfig.debug"
1797 1797
1798 config DEBUG_WQ_FORCE_RR_CPU 1798 config DEBUG_WQ_FORCE_RR_CPU
1799 bool "Force round-robin CPU selection 1799 bool "Force round-robin CPU selection for unbound work items"
1800 depends on DEBUG_KERNEL 1800 depends on DEBUG_KERNEL
1801 default n 1801 default n
1802 help 1802 help
1803 Workqueue used to implicitly guaran 1803 Workqueue used to implicitly guarantee that work items queued
1804 without explicit CPU specified are 1804 without explicit CPU specified are put on the local CPU. This
1805 guarantee is no longer true and whi 1805 guarantee is no longer true and while local CPU is still
1806 preferred work items may be put on 1806 preferred work items may be put on foreign CPUs. Kernel
1807 parameter "workqueue.debug_force_rr 1807 parameter "workqueue.debug_force_rr_cpu" is added to force
1808 round-robin CPU selection to flush 1808 round-robin CPU selection to flush out usages which depend on the
1809 now broken guarantee. This config 1809 now broken guarantee. This config option enables the debug
1810 feature by default. When enabled, 1810 feature by default. When enabled, memory and cache locality will
1811 be impacted. 1811 be impacted.
1812 1812
1813 config CPU_HOTPLUG_STATE_CONTROL 1813 config CPU_HOTPLUG_STATE_CONTROL
1814 bool "Enable CPU hotplug state contro 1814 bool "Enable CPU hotplug state control"
1815 depends on DEBUG_KERNEL 1815 depends on DEBUG_KERNEL
1816 depends on HOTPLUG_CPU 1816 depends on HOTPLUG_CPU
1817 default n 1817 default n
1818 help 1818 help
1819 Allows to write steps between "offl 1819 Allows to write steps between "offline" and "online" to the CPUs
1820 sysfs target file so states can be 1820 sysfs target file so states can be stepped granular. This is a debug
1821 option for now as the hotplug machi 1821 option for now as the hotplug machinery cannot be stopped and
1822 restarted at arbitrary points yet. 1822 restarted at arbitrary points yet.
1823 1823
1824 Say N if your are unsure. 1824 Say N if your are unsure.
1825 1825
1826 config LATENCYTOP 1826 config LATENCYTOP
1827 bool "Latency measuring infrastructur 1827 bool "Latency measuring infrastructure"
1828 depends on DEBUG_KERNEL 1828 depends on DEBUG_KERNEL
1829 depends on STACKTRACE_SUPPORT 1829 depends on STACKTRACE_SUPPORT
1830 depends on PROC_FS 1830 depends on PROC_FS
1831 depends on FRAME_POINTER || MIPS || P 1831 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1832 select KALLSYMS 1832 select KALLSYMS
1833 select KALLSYMS_ALL 1833 select KALLSYMS_ALL
1834 select STACKTRACE 1834 select STACKTRACE
1835 select SCHEDSTATS 1835 select SCHEDSTATS
1836 help 1836 help
1837 Enable this option if you want to u 1837 Enable this option if you want to use the LatencyTOP tool
1838 to find out which userspace is bloc 1838 to find out which userspace is blocking on what kernel operations.
1839 1839
1840 config DEBUG_CGROUP_REF 1840 config DEBUG_CGROUP_REF
1841 bool "Disable inlining of cgroup css 1841 bool "Disable inlining of cgroup css reference count functions"
1842 depends on DEBUG_KERNEL 1842 depends on DEBUG_KERNEL
1843 depends on CGROUPS 1843 depends on CGROUPS
1844 depends on KPROBES 1844 depends on KPROBES
1845 default n 1845 default n
1846 help 1846 help
1847 Force cgroup css reference count fu 1847 Force cgroup css reference count functions to not be inlined so
1848 that they can be kprobed for debugg 1848 that they can be kprobed for debugging.
1849 1849
1850 source "kernel/trace/Kconfig" 1850 source "kernel/trace/Kconfig"
1851 1851
1852 config PROVIDE_OHCI1394_DMA_INIT 1852 config PROVIDE_OHCI1394_DMA_INIT
1853 bool "Remote debugging over FireWire 1853 bool "Remote debugging over FireWire early on boot"
1854 depends on PCI && X86 1854 depends on PCI && X86
1855 help 1855 help
1856 If you want to debug problems which 1856 If you want to debug problems which hang or crash the kernel early
1857 on boot and the crashing machine ha 1857 on boot and the crashing machine has a FireWire port, you can use
1858 this feature to remotely access the 1858 this feature to remotely access the memory of the crashed machine
1859 over FireWire. This employs remote 1859 over FireWire. This employs remote DMA as part of the OHCI1394
1860 specification which is now the stan 1860 specification which is now the standard for FireWire controllers.
1861 1861
1862 With remote DMA, you can monitor th 1862 With remote DMA, you can monitor the printk buffer remotely using
1863 firescope and access all memory bel 1863 firescope and access all memory below 4GB using fireproxy from gdb.
1864 Even controlling a kernel debugger 1864 Even controlling a kernel debugger is possible using remote DMA.
1865 1865
1866 Usage: 1866 Usage:
1867 1867
1868 If ohci1394_dma=early is used as bo 1868 If ohci1394_dma=early is used as boot parameter, it will initialize
1869 all OHCI1394 controllers which are 1869 all OHCI1394 controllers which are found in the PCI config space.
1870 1870
1871 As all changes to the FireWire bus 1871 As all changes to the FireWire bus such as enabling and disabling
1872 devices cause a bus reset and there 1872 devices cause a bus reset and thereby disable remote DMA for all
1873 devices, be sure to have the cable 1873 devices, be sure to have the cable plugged and FireWire enabled on
1874 the debugging host before booting t 1874 the debugging host before booting the debug target for debugging.
1875 1875
1876 This code (~1k) is freed after boot 1876 This code (~1k) is freed after boot. By then, the firewire stack
1877 in charge of the OHCI-1394 controll 1877 in charge of the OHCI-1394 controllers should be used instead.
1878 1878
1879 See Documentation/core-api/debuggin 1879 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1880 1880
1881 source "samples/Kconfig" 1881 source "samples/Kconfig"
1882 1882
1883 config ARCH_HAS_DEVMEM_IS_ALLOWED 1883 config ARCH_HAS_DEVMEM_IS_ALLOWED
1884 bool 1884 bool
1885 1885
1886 config STRICT_DEVMEM 1886 config STRICT_DEVMEM
1887 bool "Filter access to /dev/mem" 1887 bool "Filter access to /dev/mem"
1888 depends on MMU && DEVMEM 1888 depends on MMU && DEVMEM
1889 depends on ARCH_HAS_DEVMEM_IS_ALLOWED 1889 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1890 default y if PPC || X86 || ARM64 1890 default y if PPC || X86 || ARM64
1891 help 1891 help
1892 If this option is disabled, you all 1892 If this option is disabled, you allow userspace (root) access to all
1893 of memory, including kernel and use 1893 of memory, including kernel and userspace memory. Accidental
1894 access to this is obviously disastr 1894 access to this is obviously disastrous, but specific access can
1895 be used by people debugging the ker 1895 be used by people debugging the kernel. Note that with PAT support
1896 enabled, even in this case there ar 1896 enabled, even in this case there are restrictions on /dev/mem
1897 use due to the cache aliasing requi 1897 use due to the cache aliasing requirements.
1898 1898
1899 If this option is switched on, and 1899 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1900 file only allows userspace access t 1900 file only allows userspace access to PCI space and the BIOS code and
1901 data regions. This is sufficient f 1901 data regions. This is sufficient for dosemu and X and all common
1902 users of /dev/mem. 1902 users of /dev/mem.
1903 1903
1904 If in doubt, say Y. 1904 If in doubt, say Y.
1905 1905
1906 config IO_STRICT_DEVMEM 1906 config IO_STRICT_DEVMEM
1907 bool "Filter I/O access to /dev/mem" 1907 bool "Filter I/O access to /dev/mem"
1908 depends on STRICT_DEVMEM 1908 depends on STRICT_DEVMEM
1909 help 1909 help
1910 If this option is disabled, you all 1910 If this option is disabled, you allow userspace (root) access to all
1911 io-memory regardless of whether a d 1911 io-memory regardless of whether a driver is actively using that
1912 range. Accidental access to this i 1912 range. Accidental access to this is obviously disastrous, but
1913 specific access can be used by peop 1913 specific access can be used by people debugging kernel drivers.
1914 1914
1915 If this option is switched on, the 1915 If this option is switched on, the /dev/mem file only allows
1916 userspace access to *idle* io-memor 1916 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1917 may break traditional users of /dev 1917 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1918 if the driver using a given range c 1918 if the driver using a given range cannot be disabled.
1919 1919
1920 If in doubt, say Y. 1920 If in doubt, say Y.
1921 1921
1922 menu "$(SRCARCH) Debugging" 1922 menu "$(SRCARCH) Debugging"
1923 1923
1924 source "arch/$(SRCARCH)/Kconfig.debug" 1924 source "arch/$(SRCARCH)/Kconfig.debug"
1925 1925
1926 endmenu 1926 endmenu
1927 1927
1928 menu "Kernel Testing and Coverage" 1928 menu "Kernel Testing and Coverage"
1929 1929
1930 source "lib/kunit/Kconfig" 1930 source "lib/kunit/Kconfig"
1931 1931
1932 config NOTIFIER_ERROR_INJECTION 1932 config NOTIFIER_ERROR_INJECTION
1933 tristate "Notifier error injection" 1933 tristate "Notifier error injection"
1934 depends on DEBUG_KERNEL 1934 depends on DEBUG_KERNEL
1935 select DEBUG_FS 1935 select DEBUG_FS
1936 help 1936 help
1937 This option provides the ability to 1937 This option provides the ability to inject artificial errors to
1938 specified notifier chain callbacks. 1938 specified notifier chain callbacks. It is useful to test the error
1939 handling of notifier call chain fai 1939 handling of notifier call chain failures.
1940 1940
1941 Say N if unsure. 1941 Say N if unsure.
1942 1942
1943 config PM_NOTIFIER_ERROR_INJECT 1943 config PM_NOTIFIER_ERROR_INJECT
1944 tristate "PM notifier error injection 1944 tristate "PM notifier error injection module"
1945 depends on PM && NOTIFIER_ERROR_INJEC 1945 depends on PM && NOTIFIER_ERROR_INJECTION
1946 default m if PM_DEBUG 1946 default m if PM_DEBUG
1947 help 1947 help
1948 This option provides the ability to 1948 This option provides the ability to inject artificial errors to
1949 PM notifier chain callbacks. It is 1949 PM notifier chain callbacks. It is controlled through debugfs
1950 interface /sys/kernel/debug/notifie 1950 interface /sys/kernel/debug/notifier-error-inject/pm
1951 1951
1952 If the notifier call chain should b 1952 If the notifier call chain should be failed with some events
1953 notified, write the error code to " 1953 notified, write the error code to "actions/<notifier event>/error".
1954 1954
1955 Example: Inject PM suspend error (- 1955 Example: Inject PM suspend error (-12 = -ENOMEM)
1956 1956
1957 # cd /sys/kernel/debug/notifier-err 1957 # cd /sys/kernel/debug/notifier-error-inject/pm/
1958 # echo -12 > actions/PM_SUSPEND_PRE 1958 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1959 # echo mem > /sys/power/state 1959 # echo mem > /sys/power/state
1960 bash: echo: write error: Cannot all 1960 bash: echo: write error: Cannot allocate memory
1961 1961
1962 To compile this code as a module, c 1962 To compile this code as a module, choose M here: the module will
1963 be called pm-notifier-error-inject. 1963 be called pm-notifier-error-inject.
1964 1964
1965 If unsure, say N. 1965 If unsure, say N.
1966 1966
1967 config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1967 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1968 tristate "OF reconfig notifier error 1968 tristate "OF reconfig notifier error injection module"
1969 depends on OF_DYNAMIC && NOTIFIER_ERR 1969 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1970 help 1970 help
1971 This option provides the ability to 1971 This option provides the ability to inject artificial errors to
1972 OF reconfig notifier chain callback 1972 OF reconfig notifier chain callbacks. It is controlled
1973 through debugfs interface under 1973 through debugfs interface under
1974 /sys/kernel/debug/notifier-error-in 1974 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1975 1975
1976 If the notifier call chain should b 1976 If the notifier call chain should be failed with some events
1977 notified, write the error code to " 1977 notified, write the error code to "actions/<notifier event>/error".
1978 1978
1979 To compile this code as a module, c 1979 To compile this code as a module, choose M here: the module will
1980 be called of-reconfig-notifier-erro 1980 be called of-reconfig-notifier-error-inject.
1981 1981
1982 If unsure, say N. 1982 If unsure, say N.
1983 1983
1984 config NETDEV_NOTIFIER_ERROR_INJECT 1984 config NETDEV_NOTIFIER_ERROR_INJECT
1985 tristate "Netdev notifier error injec 1985 tristate "Netdev notifier error injection module"
1986 depends on NET && NOTIFIER_ERROR_INJE 1986 depends on NET && NOTIFIER_ERROR_INJECTION
1987 help 1987 help
1988 This option provides the ability to 1988 This option provides the ability to inject artificial errors to
1989 netdevice notifier chain callbacks. 1989 netdevice notifier chain callbacks. It is controlled through debugfs
1990 interface /sys/kernel/debug/notifie 1990 interface /sys/kernel/debug/notifier-error-inject/netdev
1991 1991
1992 If the notifier call chain should b 1992 If the notifier call chain should be failed with some events
1993 notified, write the error code to " 1993 notified, write the error code to "actions/<notifier event>/error".
1994 1994
1995 Example: Inject netdevice mtu chang 1995 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1996 1996
1997 # cd /sys/kernel/debug/notifier-err 1997 # cd /sys/kernel/debug/notifier-error-inject/netdev
1998 # echo -22 > actions/NETDEV_CHANGEM 1998 # echo -22 > actions/NETDEV_CHANGEMTU/error
1999 # ip link set eth0 mtu 1024 1999 # ip link set eth0 mtu 1024
2000 RTNETLINK answers: Invalid argument 2000 RTNETLINK answers: Invalid argument
2001 2001
2002 To compile this code as a module, c 2002 To compile this code as a module, choose M here: the module will
2003 be called netdev-notifier-error-inj 2003 be called netdev-notifier-error-inject.
2004 2004
2005 If unsure, say N. 2005 If unsure, say N.
2006 2006
2007 config FUNCTION_ERROR_INJECTION 2007 config FUNCTION_ERROR_INJECTION
2008 bool "Fault-injections of functions" 2008 bool "Fault-injections of functions"
2009 depends on HAVE_FUNCTION_ERROR_INJECT 2009 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2010 help 2010 help
2011 Add fault injections into various f 2011 Add fault injections into various functions that are annotated with
2012 ALLOW_ERROR_INJECTION() in the kern 2012 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2013 value of these functions. This is u 2013 value of these functions. This is useful to test error paths of code.
2014 2014
2015 If unsure, say N 2015 If unsure, say N
2016 2016
2017 config FAULT_INJECTION 2017 config FAULT_INJECTION
2018 bool "Fault-injection framework" 2018 bool "Fault-injection framework"
2019 depends on DEBUG_KERNEL 2019 depends on DEBUG_KERNEL
2020 help 2020 help
2021 Provide fault-injection framework. 2021 Provide fault-injection framework.
2022 For more details, see Documentation 2022 For more details, see Documentation/fault-injection/.
2023 2023
2024 config FAILSLAB 2024 config FAILSLAB
2025 bool "Fault-injection capability for 2025 bool "Fault-injection capability for kmalloc"
2026 depends on FAULT_INJECTION 2026 depends on FAULT_INJECTION
2027 help 2027 help
2028 Provide fault-injection capability 2028 Provide fault-injection capability for kmalloc.
2029 2029
2030 config FAIL_PAGE_ALLOC 2030 config FAIL_PAGE_ALLOC
2031 bool "Fault-injection capability for 2031 bool "Fault-injection capability for alloc_pages()"
2032 depends on FAULT_INJECTION 2032 depends on FAULT_INJECTION
2033 help 2033 help
2034 Provide fault-injection capability 2034 Provide fault-injection capability for alloc_pages().
2035 2035
2036 config FAULT_INJECTION_USERCOPY 2036 config FAULT_INJECTION_USERCOPY
2037 bool "Fault injection capability for 2037 bool "Fault injection capability for usercopy functions"
2038 depends on FAULT_INJECTION 2038 depends on FAULT_INJECTION
2039 help 2039 help
2040 Provides fault-injection capability 2040 Provides fault-injection capability to inject failures
2041 in usercopy functions (copy_from_us 2041 in usercopy functions (copy_from_user(), get_user(), ...).
2042 2042
2043 config FAIL_MAKE_REQUEST 2043 config FAIL_MAKE_REQUEST
2044 bool "Fault-injection capability for 2044 bool "Fault-injection capability for disk IO"
2045 depends on FAULT_INJECTION && BLOCK 2045 depends on FAULT_INJECTION && BLOCK
2046 help 2046 help
2047 Provide fault-injection capability 2047 Provide fault-injection capability for disk IO.
2048 2048
2049 config FAIL_IO_TIMEOUT 2049 config FAIL_IO_TIMEOUT
2050 bool "Fault-injection capability for 2050 bool "Fault-injection capability for faking disk interrupts"
2051 depends on FAULT_INJECTION && BLOCK 2051 depends on FAULT_INJECTION && BLOCK
2052 help 2052 help
2053 Provide fault-injection capability 2053 Provide fault-injection capability on end IO handling. This
2054 will make the block layer "forget" 2054 will make the block layer "forget" an interrupt as configured,
2055 thus exercising the error handling. 2055 thus exercising the error handling.
2056 2056
2057 Only works with drivers that use th 2057 Only works with drivers that use the generic timeout handling,
2058 for others it won't do anything. 2058 for others it won't do anything.
2059 2059
2060 config FAIL_FUTEX 2060 config FAIL_FUTEX
2061 bool "Fault-injection capability for 2061 bool "Fault-injection capability for futexes"
2062 select DEBUG_FS 2062 select DEBUG_FS
2063 depends on FAULT_INJECTION && FUTEX 2063 depends on FAULT_INJECTION && FUTEX
2064 help 2064 help
2065 Provide fault-injection capability 2065 Provide fault-injection capability for futexes.
2066 2066
2067 config FAULT_INJECTION_DEBUG_FS 2067 config FAULT_INJECTION_DEBUG_FS
2068 bool "Debugfs entries for fault-injec 2068 bool "Debugfs entries for fault-injection capabilities"
2069 depends on FAULT_INJECTION && SYSFS & 2069 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2070 help 2070 help
2071 Enable configuration of fault-injec 2071 Enable configuration of fault-injection capabilities via debugfs.
2072 2072
2073 config FAIL_FUNCTION 2073 config FAIL_FUNCTION
2074 bool "Fault-injection capability for 2074 bool "Fault-injection capability for functions"
2075 depends on FAULT_INJECTION_DEBUG_FS & 2075 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2076 help 2076 help
2077 Provide function-based fault-inject 2077 Provide function-based fault-injection capability.
2078 This will allow you to override a s 2078 This will allow you to override a specific function with a return
2079 with given return value. As a resul 2079 with given return value. As a result, function caller will see
2080 an error value and have to handle i 2080 an error value and have to handle it. This is useful to test the
2081 error handling in various subsystem 2081 error handling in various subsystems.
2082 2082
2083 config FAIL_MMC_REQUEST 2083 config FAIL_MMC_REQUEST
2084 bool "Fault-injection capability for 2084 bool "Fault-injection capability for MMC IO"
2085 depends on FAULT_INJECTION_DEBUG_FS & 2085 depends on FAULT_INJECTION_DEBUG_FS && MMC
2086 help 2086 help
2087 Provide fault-injection capability 2087 Provide fault-injection capability for MMC IO.
2088 This will make the mmc core return 2088 This will make the mmc core return data errors. This is
2089 useful to test the error handling i 2089 useful to test the error handling in the mmc block device
2090 and to test how the mmc host driver 2090 and to test how the mmc host driver handles retries from
2091 the block device. 2091 the block device.
2092 2092
2093 config FAIL_SUNRPC 2093 config FAIL_SUNRPC
2094 bool "Fault-injection capability for 2094 bool "Fault-injection capability for SunRPC"
2095 depends on FAULT_INJECTION_DEBUG_FS & 2095 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2096 help 2096 help
2097 Provide fault-injection capability 2097 Provide fault-injection capability for SunRPC and
2098 its consumers. 2098 its consumers.
2099 2099
2100 config FAULT_INJECTION_CONFIGFS 2100 config FAULT_INJECTION_CONFIGFS
2101 bool "Configfs interface for fault-in 2101 bool "Configfs interface for fault-injection capabilities"
2102 depends on FAULT_INJECTION 2102 depends on FAULT_INJECTION
2103 select CONFIGFS_FS 2103 select CONFIGFS_FS
2104 help 2104 help
2105 This option allows configfs-based d 2105 This option allows configfs-based drivers to dynamically configure
2106 fault-injection via configfs. Each 2106 fault-injection via configfs. Each parameter for driver-specific
2107 fault-injection can be made visible 2107 fault-injection can be made visible as a configfs attribute in a
2108 configfs group. 2108 configfs group.
2109 2109
2110 2110
2111 config FAULT_INJECTION_STACKTRACE_FILTER 2111 config FAULT_INJECTION_STACKTRACE_FILTER
2112 bool "stacktrace filter for fault-inj 2112 bool "stacktrace filter for fault-injection capabilities"
2113 depends on FAULT_INJECTION 2113 depends on FAULT_INJECTION
2114 depends on (FAULT_INJECTION_DEBUG_FS 2114 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2115 select STACKTRACE 2115 select STACKTRACE
2116 depends on FRAME_POINTER || MIPS || P 2116 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2117 help 2117 help
2118 Provide stacktrace filter for fault 2118 Provide stacktrace filter for fault-injection capabilities
2119 2119
2120 config ARCH_HAS_KCOV 2120 config ARCH_HAS_KCOV
2121 bool 2121 bool
2122 help 2122 help
2123 An architecture should select this 2123 An architecture should select this when it can successfully
2124 build and run with CONFIG_KCOV. Thi 2124 build and run with CONFIG_KCOV. This typically requires
2125 disabling instrumentation for some 2125 disabling instrumentation for some early boot code.
2126 2126
2127 config CC_HAS_SANCOV_TRACE_PC 2127 config CC_HAS_SANCOV_TRACE_PC
2128 def_bool $(cc-option,-fsanitize-cover 2128 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2129 2129
2130 2130
2131 config KCOV 2131 config KCOV
2132 bool "Code coverage for fuzzing" 2132 bool "Code coverage for fuzzing"
2133 depends on ARCH_HAS_KCOV 2133 depends on ARCH_HAS_KCOV
2134 depends on CC_HAS_SANCOV_TRACE_PC || 2134 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2135 depends on !ARCH_WANTS_NO_INSTR || HA 2135 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2136 GCC_VERSION >= 120000 || C 2136 GCC_VERSION >= 120000 || CC_IS_CLANG
2137 select DEBUG_FS 2137 select DEBUG_FS
2138 select GCC_PLUGIN_SANCOV if !CC_HAS_S 2138 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2139 select OBJTOOL if HAVE_NOINSTR_HACK 2139 select OBJTOOL if HAVE_NOINSTR_HACK
2140 help 2140 help
2141 KCOV exposes kernel code coverage i 2141 KCOV exposes kernel code coverage information in a form suitable
2142 for coverage-guided fuzzing (random 2142 for coverage-guided fuzzing (randomized testing).
2143 2143
2144 For more details, see Documentation 2144 For more details, see Documentation/dev-tools/kcov.rst.
2145 2145
2146 config KCOV_ENABLE_COMPARISONS 2146 config KCOV_ENABLE_COMPARISONS
2147 bool "Enable comparison operands coll 2147 bool "Enable comparison operands collection by KCOV"
2148 depends on KCOV 2148 depends on KCOV
2149 depends on $(cc-option,-fsanitize-cov 2149 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2150 help 2150 help
2151 KCOV also exposes operands of every 2151 KCOV also exposes operands of every comparison in the instrumented
2152 code along with operand sizes and P 2152 code along with operand sizes and PCs of the comparison instructions.
2153 These operands can be used by fuzzi 2153 These operands can be used by fuzzing engines to improve the quality
2154 of fuzzing coverage. 2154 of fuzzing coverage.
2155 2155
2156 config KCOV_INSTRUMENT_ALL 2156 config KCOV_INSTRUMENT_ALL
2157 bool "Instrument all code by default" 2157 bool "Instrument all code by default"
2158 depends on KCOV 2158 depends on KCOV
2159 default y 2159 default y
2160 help 2160 help
2161 If you are doing generic system cal 2161 If you are doing generic system call fuzzing (like e.g. syzkaller),
2162 then you will want to instrument th 2162 then you will want to instrument the whole kernel and you should
2163 say y here. If you are doing more t 2163 say y here. If you are doing more targeted fuzzing (like e.g.
2164 filesystem fuzzing with AFL) then y 2164 filesystem fuzzing with AFL) then you will want to enable coverage
2165 for more specific subsets of files, 2165 for more specific subsets of files, and should say n here.
2166 2166
2167 config KCOV_IRQ_AREA_SIZE 2167 config KCOV_IRQ_AREA_SIZE
2168 hex "Size of interrupt coverage colle 2168 hex "Size of interrupt coverage collection area in words"
2169 depends on KCOV 2169 depends on KCOV
2170 default 0x40000 2170 default 0x40000
2171 help 2171 help
2172 KCOV uses preallocated per-cpu area 2172 KCOV uses preallocated per-cpu areas to collect coverage from
2173 soft interrupts. This specifies the 2173 soft interrupts. This specifies the size of those areas in the
2174 number of unsigned long words. 2174 number of unsigned long words.
2175 2175
2176 menuconfig RUNTIME_TESTING_MENU 2176 menuconfig RUNTIME_TESTING_MENU
2177 bool "Runtime Testing" 2177 bool "Runtime Testing"
2178 default y 2178 default y
2179 2179
2180 if RUNTIME_TESTING_MENU 2180 if RUNTIME_TESTING_MENU
2181 2181
2182 config TEST_DHRY 2182 config TEST_DHRY
2183 tristate "Dhrystone benchmark test" 2183 tristate "Dhrystone benchmark test"
2184 help 2184 help
2185 Enable this to include the Dhryston 2185 Enable this to include the Dhrystone 2.1 benchmark. This test
2186 calculates the number of Dhrystones 2186 calculates the number of Dhrystones per second, and the number of
2187 DMIPS (Dhrystone MIPS) obtained whe 2187 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2188 by 1757 (the number of Dhrystones p 2188 by 1757 (the number of Dhrystones per second obtained on the VAX
2189 11/780, nominally a 1 MIPS machine) 2189 11/780, nominally a 1 MIPS machine).
2190 2190
2191 To run the benchmark, it needs to b 2191 To run the benchmark, it needs to be enabled explicitly, either from
2192 the kernel command line (when built 2192 the kernel command line (when built-in), or from userspace (when
2193 built-in or modular). 2193 built-in or modular).
2194 2194
2195 Run once during kernel boot: 2195 Run once during kernel boot:
2196 2196
2197 test_dhry.run 2197 test_dhry.run
2198 2198
2199 Set number of iterations from kerne 2199 Set number of iterations from kernel command line:
2200 2200
2201 test_dhry.iterations=<n> 2201 test_dhry.iterations=<n>
2202 2202
2203 Set number of iterations from users 2203 Set number of iterations from userspace:
2204 2204
2205 echo <n> > /sys/module/test_dhr 2205 echo <n> > /sys/module/test_dhry/parameters/iterations
2206 2206
2207 Trigger manual run from userspace: 2207 Trigger manual run from userspace:
2208 2208
2209 echo y > /sys/module/test_dhry/ 2209 echo y > /sys/module/test_dhry/parameters/run
2210 2210
2211 If the number of iterations is <= 0 2211 If the number of iterations is <= 0, the test will devise a suitable
2212 number of iterations (test runs for 2212 number of iterations (test runs for at least 2s) automatically.
2213 This process takes ca. 4s. 2213 This process takes ca. 4s.
2214 2214
2215 If unsure, say N. 2215 If unsure, say N.
2216 2216
2217 config LKDTM 2217 config LKDTM
2218 tristate "Linux Kernel Dump Test Tool 2218 tristate "Linux Kernel Dump Test Tool Module"
2219 depends on DEBUG_FS 2219 depends on DEBUG_FS
2220 help 2220 help
2221 This module enables testing of the di 2221 This module enables testing of the different dumping mechanisms by
2222 inducing system failures at predefine 2222 inducing system failures at predefined crash points.
2223 If you don't need it: say N 2223 If you don't need it: say N
2224 Choose M here to compile this code as 2224 Choose M here to compile this code as a module. The module will be
2225 called lkdtm. 2225 called lkdtm.
2226 2226
2227 Documentation on how to use the modul 2227 Documentation on how to use the module can be found in
2228 Documentation/fault-injection/provoke 2228 Documentation/fault-injection/provoke-crashes.rst
2229 2229
2230 config CPUMASK_KUNIT_TEST 2230 config CPUMASK_KUNIT_TEST
2231 tristate "KUnit test for cpumask" if 2231 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2232 depends on KUNIT 2232 depends on KUNIT
2233 default KUNIT_ALL_TESTS 2233 default KUNIT_ALL_TESTS
2234 help 2234 help
2235 Enable to turn on cpumask tests, ru 2235 Enable to turn on cpumask tests, running at boot or module load time.
2236 2236
2237 For more information on KUnit and u 2237 For more information on KUnit and unit tests in general, please refer
2238 to the KUnit documentation in Docum 2238 to the KUnit documentation in Documentation/dev-tools/kunit/.
2239 2239
2240 If unsure, say N. 2240 If unsure, say N.
2241 2241
2242 config TEST_LIST_SORT 2242 config TEST_LIST_SORT
2243 tristate "Linked list sorting test" i 2243 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2244 depends on KUNIT 2244 depends on KUNIT
2245 default KUNIT_ALL_TESTS 2245 default KUNIT_ALL_TESTS
2246 help 2246 help
2247 Enable this to turn on 'list_sort() 2247 Enable this to turn on 'list_sort()' function test. This test is
2248 executed only once during system bo 2248 executed only once during system boot (so affects only boot time),
2249 or at module load time. 2249 or at module load time.
2250 2250
2251 If unsure, say N. 2251 If unsure, say N.
2252 2252
2253 config TEST_MIN_HEAP 2253 config TEST_MIN_HEAP
2254 tristate "Min heap test" 2254 tristate "Min heap test"
2255 depends on DEBUG_KERNEL || m 2255 depends on DEBUG_KERNEL || m
2256 help 2256 help
2257 Enable this to turn on min heap fun 2257 Enable this to turn on min heap function tests. This test is
2258 executed only once during system bo 2258 executed only once during system boot (so affects only boot time),
2259 or at module load time. 2259 or at module load time.
2260 2260
2261 If unsure, say N. 2261 If unsure, say N.
2262 2262
2263 config TEST_SORT 2263 config TEST_SORT
2264 tristate "Array-based sort test" if ! 2264 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2265 depends on KUNIT 2265 depends on KUNIT
2266 default KUNIT_ALL_TESTS 2266 default KUNIT_ALL_TESTS
2267 help 2267 help
2268 This option enables the self-test f 2268 This option enables the self-test function of 'sort()' at boot,
2269 or at module load time. 2269 or at module load time.
2270 2270
2271 If unsure, say N. 2271 If unsure, say N.
2272 2272
2273 config TEST_DIV64 2273 config TEST_DIV64
2274 tristate "64bit/32bit division and mo 2274 tristate "64bit/32bit division and modulo test"
2275 depends on DEBUG_KERNEL || m 2275 depends on DEBUG_KERNEL || m
2276 help 2276 help
2277 Enable this to turn on 'do_div()' f 2277 Enable this to turn on 'do_div()' function test. This test is
2278 executed only once during system bo 2278 executed only once during system boot (so affects only boot time),
2279 or at module load time. 2279 or at module load time.
2280 2280
2281 If unsure, say N. 2281 If unsure, say N.
2282 2282
2283 config TEST_IOV_ITER 2283 config TEST_IOV_ITER
2284 tristate "Test iov_iter operation" if 2284 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2285 depends on KUNIT 2285 depends on KUNIT
2286 depends on MMU 2286 depends on MMU
2287 default KUNIT_ALL_TESTS 2287 default KUNIT_ALL_TESTS
2288 help 2288 help
2289 Enable this to turn on testing of t 2289 Enable this to turn on testing of the operation of the I/O iterator
2290 (iov_iter). This test is executed o 2290 (iov_iter). This test is executed only once during system boot (so
2291 affects only boot time), or at modu 2291 affects only boot time), or at module load time.
2292 2292
2293 If unsure, say N. 2293 If unsure, say N.
2294 2294
2295 config KPROBES_SANITY_TEST 2295 config KPROBES_SANITY_TEST
2296 tristate "Kprobes sanity tests" if !K 2296 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2297 depends on DEBUG_KERNEL 2297 depends on DEBUG_KERNEL
2298 depends on KPROBES 2298 depends on KPROBES
2299 depends on KUNIT 2299 depends on KUNIT
2300 select STACKTRACE if ARCH_CORRECT_STA 2300 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2301 default KUNIT_ALL_TESTS 2301 default KUNIT_ALL_TESTS
2302 help 2302 help
2303 This option provides for testing ba 2303 This option provides for testing basic kprobes functionality on
2304 boot. Samples of kprobe and kretpro 2304 boot. Samples of kprobe and kretprobe are inserted and
2305 verified for functionality. 2305 verified for functionality.
2306 2306
2307 Say N if you are unsure. 2307 Say N if you are unsure.
2308 2308
2309 config FPROBE_SANITY_TEST 2309 config FPROBE_SANITY_TEST
2310 bool "Self test for fprobe" 2310 bool "Self test for fprobe"
2311 depends on DEBUG_KERNEL 2311 depends on DEBUG_KERNEL
2312 depends on FPROBE 2312 depends on FPROBE
2313 depends on KUNIT=y 2313 depends on KUNIT=y
2314 help 2314 help
2315 This option will enable testing the 2315 This option will enable testing the fprobe when the system boot.
2316 A series of tests are made to verif 2316 A series of tests are made to verify that the fprobe is functioning
2317 properly. 2317 properly.
2318 2318
2319 Say N if you are unsure. 2319 Say N if you are unsure.
2320 2320
2321 config BACKTRACE_SELF_TEST 2321 config BACKTRACE_SELF_TEST
2322 tristate "Self test for the backtrace 2322 tristate "Self test for the backtrace code"
2323 depends on DEBUG_KERNEL 2323 depends on DEBUG_KERNEL
2324 help 2324 help
2325 This option provides a kernel modul 2325 This option provides a kernel module that can be used to test
2326 the kernel stack backtrace code. Th 2326 the kernel stack backtrace code. This option is not useful
2327 for distributions or general kernel 2327 for distributions or general kernels, but only for kernel
2328 developers working on architecture 2328 developers working on architecture code.
2329 2329
2330 Note that if you want to also test 2330 Note that if you want to also test saved backtraces, you will
2331 have to enable STACKTRACE as well. 2331 have to enable STACKTRACE as well.
2332 2332
2333 Say N if you are unsure. 2333 Say N if you are unsure.
2334 2334
2335 config TEST_REF_TRACKER 2335 config TEST_REF_TRACKER
2336 tristate "Self test for reference tra 2336 tristate "Self test for reference tracker"
2337 depends on DEBUG_KERNEL && STACKTRACE 2337 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2338 select REF_TRACKER 2338 select REF_TRACKER
2339 help 2339 help
2340 This option provides a kernel modul 2340 This option provides a kernel module performing tests
2341 using reference tracker infrastruct 2341 using reference tracker infrastructure.
2342 2342
2343 Say N if you are unsure. 2343 Say N if you are unsure.
2344 2344
2345 config RBTREE_TEST 2345 config RBTREE_TEST
2346 tristate "Red-Black tree test" 2346 tristate "Red-Black tree test"
2347 depends on DEBUG_KERNEL 2347 depends on DEBUG_KERNEL
2348 help 2348 help
2349 A benchmark measuring the performan 2349 A benchmark measuring the performance of the rbtree library.
2350 Also includes rbtree invariant chec 2350 Also includes rbtree invariant checks.
2351 2351
2352 config REED_SOLOMON_TEST 2352 config REED_SOLOMON_TEST
2353 tristate "Reed-Solomon library test" 2353 tristate "Reed-Solomon library test"
2354 depends on DEBUG_KERNEL || m 2354 depends on DEBUG_KERNEL || m
2355 select REED_SOLOMON 2355 select REED_SOLOMON
2356 select REED_SOLOMON_ENC16 2356 select REED_SOLOMON_ENC16
2357 select REED_SOLOMON_DEC16 2357 select REED_SOLOMON_DEC16
2358 help 2358 help
2359 This option enables the self-test f 2359 This option enables the self-test function of rslib at boot,
2360 or at module load time. 2360 or at module load time.
2361 2361
2362 If unsure, say N. 2362 If unsure, say N.
2363 2363
2364 config INTERVAL_TREE_TEST 2364 config INTERVAL_TREE_TEST
2365 tristate "Interval tree test" 2365 tristate "Interval tree test"
2366 depends on DEBUG_KERNEL 2366 depends on DEBUG_KERNEL
2367 select INTERVAL_TREE 2367 select INTERVAL_TREE
2368 help 2368 help
2369 A benchmark measuring the performan 2369 A benchmark measuring the performance of the interval tree library
2370 2370
2371 config PERCPU_TEST 2371 config PERCPU_TEST
2372 tristate "Per cpu operations test" 2372 tristate "Per cpu operations test"
2373 depends on m && DEBUG_KERNEL 2373 depends on m && DEBUG_KERNEL
2374 help 2374 help
2375 Enable this option to build test mo 2375 Enable this option to build test module which validates per-cpu
2376 operations. 2376 operations.
2377 2377
2378 If unsure, say N. 2378 If unsure, say N.
2379 2379
2380 config ATOMIC64_SELFTEST 2380 config ATOMIC64_SELFTEST
2381 tristate "Perform an atomic64_t self- 2381 tristate "Perform an atomic64_t self-test"
2382 help 2382 help
2383 Enable this option to test the atom 2383 Enable this option to test the atomic64_t functions at boot or
2384 at module load time. 2384 at module load time.
2385 2385
2386 If unsure, say N. 2386 If unsure, say N.
2387 2387
2388 config ASYNC_RAID6_TEST 2388 config ASYNC_RAID6_TEST
2389 tristate "Self test for hardware acce 2389 tristate "Self test for hardware accelerated raid6 recovery"
2390 depends on ASYNC_RAID6_RECOV 2390 depends on ASYNC_RAID6_RECOV
2391 select ASYNC_MEMCPY 2391 select ASYNC_MEMCPY
2392 help 2392 help
2393 This is a one-shot self test that p 2393 This is a one-shot self test that permutes through the
2394 recovery of all the possible two di 2394 recovery of all the possible two disk failure scenarios for a
2395 N-disk array. Recovery is performe 2395 N-disk array. Recovery is performed with the asynchronous
2396 raid6 recovery routines, and will o 2396 raid6 recovery routines, and will optionally use an offload
2397 engine if one is available. 2397 engine if one is available.
2398 2398
2399 If unsure, say N. 2399 If unsure, say N.
2400 2400
2401 config TEST_HEXDUMP 2401 config TEST_HEXDUMP
2402 tristate "Test functions located in t 2402 tristate "Test functions located in the hexdump module at runtime"
2403 2403
2404 config STRING_KUNIT_TEST 2404 config STRING_KUNIT_TEST
2405 tristate "KUnit test string functions 2405 tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2406 depends on KUNIT 2406 depends on KUNIT
2407 default KUNIT_ALL_TESTS 2407 default KUNIT_ALL_TESTS
2408 2408
2409 config STRING_HELPERS_KUNIT_TEST 2409 config STRING_HELPERS_KUNIT_TEST
2410 tristate "KUnit test string helpers a 2410 tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2411 depends on KUNIT 2411 depends on KUNIT
2412 default KUNIT_ALL_TESTS 2412 default KUNIT_ALL_TESTS
2413 2413
2414 config TEST_KSTRTOX 2414 config TEST_KSTRTOX
2415 tristate "Test kstrto*() family of fu 2415 tristate "Test kstrto*() family of functions at runtime"
2416 2416
2417 config TEST_PRINTF 2417 config TEST_PRINTF
2418 tristate "Test printf() family of fun 2418 tristate "Test printf() family of functions at runtime"
2419 2419
2420 config TEST_SCANF 2420 config TEST_SCANF
2421 tristate "Test scanf() family of func 2421 tristate "Test scanf() family of functions at runtime"
2422 2422
2423 config TEST_BITMAP 2423 config TEST_BITMAP
2424 tristate "Test bitmap_*() family of f 2424 tristate "Test bitmap_*() family of functions at runtime"
2425 help 2425 help
2426 Enable this option to test the bitm 2426 Enable this option to test the bitmap functions at boot.
2427 2427
2428 If unsure, say N. 2428 If unsure, say N.
2429 2429
2430 config TEST_UUID 2430 config TEST_UUID
2431 tristate "Test functions located in t 2431 tristate "Test functions located in the uuid module at runtime"
2432 2432
2433 config TEST_XARRAY 2433 config TEST_XARRAY
2434 tristate "Test the XArray code at run 2434 tristate "Test the XArray code at runtime"
2435 2435
2436 config TEST_MAPLE_TREE 2436 config TEST_MAPLE_TREE
2437 tristate "Test the Maple Tree code at 2437 tristate "Test the Maple Tree code at runtime or module load"
2438 help 2438 help
2439 Enable this option to test the mapl 2439 Enable this option to test the maple tree code functions at boot, or
2440 when the module is loaded. Enable " 2440 when the module is loaded. Enable "Debug Maple Trees" will enable
2441 more verbose output on failures. 2441 more verbose output on failures.
2442 2442
2443 If unsure, say N. 2443 If unsure, say N.
2444 2444
2445 config TEST_RHASHTABLE 2445 config TEST_RHASHTABLE
2446 tristate "Perform selftest on resizab 2446 tristate "Perform selftest on resizable hash table"
2447 help 2447 help
2448 Enable this option to test the rhas 2448 Enable this option to test the rhashtable functions at boot.
2449 2449
2450 If unsure, say N. 2450 If unsure, say N.
2451 2451
2452 config TEST_IDA 2452 config TEST_IDA
2453 tristate "Perform selftest on IDA fun 2453 tristate "Perform selftest on IDA functions"
2454 2454
2455 config TEST_PARMAN 2455 config TEST_PARMAN
2456 tristate "Perform selftest on priorit 2456 tristate "Perform selftest on priority array manager"
2457 depends on PARMAN 2457 depends on PARMAN
2458 help 2458 help
2459 Enable this option to test priority 2459 Enable this option to test priority array manager on boot
2460 (or module load). 2460 (or module load).
2461 2461
2462 If unsure, say N. 2462 If unsure, say N.
2463 2463
2464 config TEST_IRQ_TIMINGS 2464 config TEST_IRQ_TIMINGS
2465 bool "IRQ timings selftest" 2465 bool "IRQ timings selftest"
2466 depends on IRQ_TIMINGS 2466 depends on IRQ_TIMINGS
2467 help 2467 help
2468 Enable this option to test the irq 2468 Enable this option to test the irq timings code on boot.
2469 2469
2470 If unsure, say N. 2470 If unsure, say N.
2471 2471
2472 config TEST_LKM 2472 config TEST_LKM
2473 tristate "Test module loading with 'h 2473 tristate "Test module loading with 'hello world' module"
2474 depends on m 2474 depends on m
2475 help 2475 help
2476 This builds the "test_module" modul 2476 This builds the "test_module" module that emits "Hello, world"
2477 on printk when loaded. It is design 2477 on printk when loaded. It is designed to be used for basic
2478 evaluation of the module loading su 2478 evaluation of the module loading subsystem (for example when
2479 validating module verification). It 2479 validating module verification). It lacks any extra dependencies,
2480 and will not normally be loaded by 2480 and will not normally be loaded by the system unless explicitly
2481 requested by name. 2481 requested by name.
2482 2482
2483 If unsure, say N. 2483 If unsure, say N.
2484 2484
2485 config TEST_BITOPS 2485 config TEST_BITOPS
2486 tristate "Test module for compilation 2486 tristate "Test module for compilation of bitops operations"
2487 help 2487 help
2488 This builds the "test_bitops" modul 2488 This builds the "test_bitops" module that is much like the
2489 TEST_LKM module except that it does 2489 TEST_LKM module except that it does a basic exercise of the
2490 set/clear_bit macros and get_count_ 2490 set/clear_bit macros and get_count_order/long to make sure there are
2491 no compiler warnings from C=1 spars 2491 no compiler warnings from C=1 sparse checker or -Wextra
2492 compilations. It has no dependencie 2492 compilations. It has no dependencies and doesn't run or load unless
2493 explicitly requested by name. for 2493 explicitly requested by name. for example: modprobe test_bitops.
2494 2494
2495 If unsure, say N. 2495 If unsure, say N.
2496 2496
2497 config TEST_VMALLOC 2497 config TEST_VMALLOC
2498 tristate "Test module for stress/perf 2498 tristate "Test module for stress/performance analysis of vmalloc allocator"
2499 default n 2499 default n
2500 depends on MMU 2500 depends on MMU
2501 depends on m 2501 depends on m
2502 help 2502 help
2503 This builds the "test_vmalloc" modu 2503 This builds the "test_vmalloc" module that should be used for
2504 stress and performance analysis. So 2504 stress and performance analysis. So, any new change for vmalloc
2505 subsystem can be evaluated from per 2505 subsystem can be evaluated from performance and stability point
2506 of view. 2506 of view.
2507 2507
2508 If unsure, say N. 2508 If unsure, say N.
2509 2509
2510 config TEST_BPF 2510 config TEST_BPF
2511 tristate "Test BPF filter functionali 2511 tristate "Test BPF filter functionality"
2512 depends on m && NET 2512 depends on m && NET
2513 help 2513 help
2514 This builds the "test_bpf" module t 2514 This builds the "test_bpf" module that runs various test vectors
2515 against the BPF interpreter or BPF 2515 against the BPF interpreter or BPF JIT compiler depending on the
2516 current setting. This is in particu 2516 current setting. This is in particular useful for BPF JIT compiler
2517 development, but also to run regres 2517 development, but also to run regression tests against changes in
2518 the interpreter code. It also enabl 2518 the interpreter code. It also enables test stubs for eBPF maps and
2519 verifier used by user space verifie 2519 verifier used by user space verifier testsuite.
2520 2520
2521 If unsure, say N. 2521 If unsure, say N.
2522 2522
2523 config TEST_BLACKHOLE_DEV 2523 config TEST_BLACKHOLE_DEV
2524 tristate "Test blackhole netdev funct 2524 tristate "Test blackhole netdev functionality"
2525 depends on m && NET 2525 depends on m && NET
2526 help 2526 help
2527 This builds the "test_blackhole_dev 2527 This builds the "test_blackhole_dev" module that validates the
2528 data path through this blackhole ne 2528 data path through this blackhole netdev.
2529 2529
2530 If unsure, say N. 2530 If unsure, say N.
2531 2531
2532 config FIND_BIT_BENCHMARK 2532 config FIND_BIT_BENCHMARK
2533 tristate "Test find_bit functions" 2533 tristate "Test find_bit functions"
2534 help 2534 help
2535 This builds the "test_find_bit" mod 2535 This builds the "test_find_bit" module that measure find_*_bit()
2536 functions performance. 2536 functions performance.
2537 2537
2538 If unsure, say N. 2538 If unsure, say N.
2539 2539
2540 config TEST_FIRMWARE 2540 config TEST_FIRMWARE
2541 tristate "Test firmware loading via u 2541 tristate "Test firmware loading via userspace interface"
2542 depends on FW_LOADER 2542 depends on FW_LOADER
2543 help 2543 help
2544 This builds the "test_firmware" mod 2544 This builds the "test_firmware" module that creates a userspace
2545 interface for testing firmware load 2545 interface for testing firmware loading. This can be used to
2546 control the triggering of firmware 2546 control the triggering of firmware loading without needing an
2547 actual firmware-using device. The c 2547 actual firmware-using device. The contents can be rechecked by
2548 userspace. 2548 userspace.
2549 2549
2550 If unsure, say N. 2550 If unsure, say N.
2551 2551
2552 config TEST_SYSCTL 2552 config TEST_SYSCTL
2553 tristate "sysctl test driver" 2553 tristate "sysctl test driver"
2554 depends on PROC_SYSCTL 2554 depends on PROC_SYSCTL
2555 help 2555 help
2556 This builds the "test_sysctl" modul 2556 This builds the "test_sysctl" module. This driver enables to test the
2557 proc sysctl interfaces available to 2557 proc sysctl interfaces available to drivers safely without affecting
2558 production knobs which might alter 2558 production knobs which might alter system functionality.
2559 2559
2560 If unsure, say N. 2560 If unsure, say N.
2561 2561
2562 config BITFIELD_KUNIT 2562 config BITFIELD_KUNIT
2563 tristate "KUnit test bitfield functio 2563 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2564 depends on KUNIT 2564 depends on KUNIT
2565 default KUNIT_ALL_TESTS 2565 default KUNIT_ALL_TESTS
2566 help 2566 help
2567 Enable this option to test the bitf 2567 Enable this option to test the bitfield functions at boot.
2568 2568
2569 KUnit tests run during boot and out 2569 KUnit tests run during boot and output the results to the debug log
2570 in TAP format (http://testanything. 2570 in TAP format (http://testanything.org/). Only useful for kernel devs
2571 running the KUnit test harness, and 2571 running the KUnit test harness, and not intended for inclusion into a
2572 production build. 2572 production build.
2573 2573
2574 For more information on KUnit and u 2574 For more information on KUnit and unit tests in general please refer
2575 to the KUnit documentation in Docum 2575 to the KUnit documentation in Documentation/dev-tools/kunit/.
2576 2576
2577 If unsure, say N. 2577 If unsure, say N.
2578 2578
2579 config CHECKSUM_KUNIT 2579 config CHECKSUM_KUNIT
2580 tristate "KUnit test checksum functio 2580 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2581 depends on KUNIT 2581 depends on KUNIT
2582 default KUNIT_ALL_TESTS 2582 default KUNIT_ALL_TESTS
2583 help 2583 help
2584 Enable this option to test the chec 2584 Enable this option to test the checksum functions at boot.
2585 2585
2586 KUnit tests run during boot and out 2586 KUnit tests run during boot and output the results to the debug log
2587 in TAP format (http://testanything. 2587 in TAP format (http://testanything.org/). Only useful for kernel devs
2588 running the KUnit test harness, and 2588 running the KUnit test harness, and not intended for inclusion into a
2589 production build. 2589 production build.
2590 2590
2591 For more information on KUnit and u 2591 For more information on KUnit and unit tests in general please refer
2592 to the KUnit documentation in Docum 2592 to the KUnit documentation in Documentation/dev-tools/kunit/.
2593 2593
2594 If unsure, say N. 2594 If unsure, say N.
2595 2595
2596 config HASH_KUNIT_TEST 2596 config HASH_KUNIT_TEST
2597 tristate "KUnit Test for integer hash 2597 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2598 depends on KUNIT 2598 depends on KUNIT
2599 default KUNIT_ALL_TESTS 2599 default KUNIT_ALL_TESTS
2600 help 2600 help
2601 Enable this option to test the kern 2601 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2602 integer (<linux/hash.h>) hash funct 2602 integer (<linux/hash.h>) hash functions on boot.
2603 2603
2604 KUnit tests run during boot and out 2604 KUnit tests run during boot and output the results to the debug log
2605 in TAP format (https://testanything 2605 in TAP format (https://testanything.org/). Only useful for kernel devs
2606 running the KUnit test harness, and 2606 running the KUnit test harness, and not intended for inclusion into a
2607 production build. 2607 production build.
2608 2608
2609 For more information on KUnit and u 2609 For more information on KUnit and unit tests in general please refer
2610 to the KUnit documentation in Docum 2610 to the KUnit documentation in Documentation/dev-tools/kunit/.
2611 2611
2612 This is intended to help people wri 2612 This is intended to help people writing architecture-specific
2613 optimized versions. If unsure, say 2613 optimized versions. If unsure, say N.
2614 2614
2615 config RESOURCE_KUNIT_TEST 2615 config RESOURCE_KUNIT_TEST
2616 tristate "KUnit test for resource API 2616 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2617 depends on KUNIT 2617 depends on KUNIT
2618 default KUNIT_ALL_TESTS 2618 default KUNIT_ALL_TESTS
2619 help 2619 help
2620 This builds the resource API unit t 2620 This builds the resource API unit test.
2621 Tests the logic of API provided by 2621 Tests the logic of API provided by resource.c and ioport.h.
2622 For more information on KUnit and u 2622 For more information on KUnit and unit tests in general please refer
2623 to the KUnit documentation in Docum 2623 to the KUnit documentation in Documentation/dev-tools/kunit/.
2624 2624
2625 If unsure, say N. 2625 If unsure, say N.
2626 2626
2627 config SYSCTL_KUNIT_TEST 2627 config SYSCTL_KUNIT_TEST
2628 tristate "KUnit test for sysctl" if ! 2628 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2629 depends on KUNIT 2629 depends on KUNIT
2630 default KUNIT_ALL_TESTS 2630 default KUNIT_ALL_TESTS
2631 help 2631 help
2632 This builds the proc sysctl unit te 2632 This builds the proc sysctl unit test, which runs on boot.
2633 Tests the API contract and implemen 2633 Tests the API contract and implementation correctness of sysctl.
2634 For more information on KUnit and u 2634 For more information on KUnit and unit tests in general please refer
2635 to the KUnit documentation in Docum 2635 to the KUnit documentation in Documentation/dev-tools/kunit/.
2636 2636
2637 If unsure, say N. 2637 If unsure, say N.
2638 2638
2639 config LIST_KUNIT_TEST 2639 config LIST_KUNIT_TEST
2640 tristate "KUnit Test for Kernel Linke 2640 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2641 depends on KUNIT 2641 depends on KUNIT
2642 default KUNIT_ALL_TESTS 2642 default KUNIT_ALL_TESTS
2643 help 2643 help
2644 This builds the linked list KUnit t 2644 This builds the linked list KUnit test suite.
2645 It tests that the API and basic fun 2645 It tests that the API and basic functionality of the list_head type
2646 and associated macros. 2646 and associated macros.
2647 2647
2648 KUnit tests run during boot and out 2648 KUnit tests run during boot and output the results to the debug log
2649 in TAP format (https://testanything 2649 in TAP format (https://testanything.org/). Only useful for kernel devs
2650 running the KUnit test harness, and 2650 running the KUnit test harness, and not intended for inclusion into a
2651 production build. 2651 production build.
2652 2652
2653 For more information on KUnit and u 2653 For more information on KUnit and unit tests in general please refer
2654 to the KUnit documentation in Docum 2654 to the KUnit documentation in Documentation/dev-tools/kunit/.
2655 2655
2656 If unsure, say N. 2656 If unsure, say N.
2657 2657
2658 config HASHTABLE_KUNIT_TEST 2658 config HASHTABLE_KUNIT_TEST
2659 tristate "KUnit Test for Kernel Hasht 2659 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2660 depends on KUNIT 2660 depends on KUNIT
2661 default KUNIT_ALL_TESTS 2661 default KUNIT_ALL_TESTS
2662 help 2662 help
2663 This builds the hashtable KUnit tes 2663 This builds the hashtable KUnit test suite.
2664 It tests the basic functionality of 2664 It tests the basic functionality of the API defined in
2665 include/linux/hashtable.h. For more 2665 include/linux/hashtable.h. For more information on KUnit and
2666 unit tests in general please refer 2666 unit tests in general please refer to the KUnit documentation
2667 in Documentation/dev-tools/kunit/. 2667 in Documentation/dev-tools/kunit/.
2668 2668
2669 If unsure, say N. 2669 If unsure, say N.
2670 2670
2671 config LINEAR_RANGES_TEST 2671 config LINEAR_RANGES_TEST
2672 tristate "KUnit test for linear_range 2672 tristate "KUnit test for linear_ranges"
2673 depends on KUNIT 2673 depends on KUNIT
2674 select LINEAR_RANGES 2674 select LINEAR_RANGES
2675 help 2675 help
2676 This builds the linear_ranges unit 2676 This builds the linear_ranges unit test, which runs on boot.
2677 Tests the linear_ranges logic corre 2677 Tests the linear_ranges logic correctness.
2678 For more information on KUnit and u 2678 For more information on KUnit and unit tests in general please refer
2679 to the KUnit documentation in Docum 2679 to the KUnit documentation in Documentation/dev-tools/kunit/.
2680 2680
2681 If unsure, say N. 2681 If unsure, say N.
2682 2682
2683 config CMDLINE_KUNIT_TEST 2683 config CMDLINE_KUNIT_TEST
2684 tristate "KUnit test for cmdline API" 2684 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2685 depends on KUNIT 2685 depends on KUNIT
2686 default KUNIT_ALL_TESTS 2686 default KUNIT_ALL_TESTS
2687 help 2687 help
2688 This builds the cmdline API unit te 2688 This builds the cmdline API unit test.
2689 Tests the logic of API provided by 2689 Tests the logic of API provided by cmdline.c.
2690 For more information on KUnit and u 2690 For more information on KUnit and unit tests in general please refer
2691 to the KUnit documentation in Docum 2691 to the KUnit documentation in Documentation/dev-tools/kunit/.
2692 2692
2693 If unsure, say N. 2693 If unsure, say N.
2694 2694
2695 config BITS_TEST 2695 config BITS_TEST
2696 tristate "KUnit test for bits.h" if ! 2696 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2697 depends on KUNIT 2697 depends on KUNIT
2698 default KUNIT_ALL_TESTS 2698 default KUNIT_ALL_TESTS
2699 help 2699 help
2700 This builds the bits unit test. 2700 This builds the bits unit test.
2701 Tests the logic of macros defined i 2701 Tests the logic of macros defined in bits.h.
2702 For more information on KUnit and u 2702 For more information on KUnit and unit tests in general please refer
2703 to the KUnit documentation in Docum 2703 to the KUnit documentation in Documentation/dev-tools/kunit/.
2704 2704
2705 If unsure, say N. 2705 If unsure, say N.
2706 2706
2707 config SLUB_KUNIT_TEST 2707 config SLUB_KUNIT_TEST
2708 tristate "KUnit test for SLUB cache e 2708 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2709 depends on SLUB_DEBUG && KUNIT 2709 depends on SLUB_DEBUG && KUNIT
2710 default KUNIT_ALL_TESTS 2710 default KUNIT_ALL_TESTS
2711 help 2711 help
2712 This builds SLUB allocator unit tes 2712 This builds SLUB allocator unit test.
2713 Tests SLUB cache debugging function 2713 Tests SLUB cache debugging functionality.
2714 For more information on KUnit and u 2714 For more information on KUnit and unit tests in general please refer
2715 to the KUnit documentation in Docum 2715 to the KUnit documentation in Documentation/dev-tools/kunit/.
2716 2716
2717 If unsure, say N. 2717 If unsure, say N.
2718 2718
2719 config RATIONAL_KUNIT_TEST 2719 config RATIONAL_KUNIT_TEST
2720 tristate "KUnit test for rational.c" 2720 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2721 depends on KUNIT && RATIONAL 2721 depends on KUNIT && RATIONAL
2722 default KUNIT_ALL_TESTS 2722 default KUNIT_ALL_TESTS
2723 help 2723 help
2724 This builds the rational math unit 2724 This builds the rational math unit test.
2725 For more information on KUnit and u 2725 For more information on KUnit and unit tests in general please refer
2726 to the KUnit documentation in Docum 2726 to the KUnit documentation in Documentation/dev-tools/kunit/.
2727 2727
2728 If unsure, say N. 2728 If unsure, say N.
2729 2729
2730 config MEMCPY_KUNIT_TEST 2730 config MEMCPY_KUNIT_TEST
2731 tristate "Test memcpy(), memmove(), a 2731 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2732 depends on KUNIT 2732 depends on KUNIT
2733 default KUNIT_ALL_TESTS 2733 default KUNIT_ALL_TESTS
2734 help 2734 help
2735 Builds unit tests for memcpy(), mem 2735 Builds unit tests for memcpy(), memmove(), and memset() functions.
2736 For more information on KUnit and u 2736 For more information on KUnit and unit tests in general please refer
2737 to the KUnit documentation in Docum 2737 to the KUnit documentation in Documentation/dev-tools/kunit/.
2738 2738
2739 If unsure, say N. 2739 If unsure, say N.
2740 2740
2741 config IS_SIGNED_TYPE_KUNIT_TEST 2741 config IS_SIGNED_TYPE_KUNIT_TEST
2742 tristate "Test is_signed_type() macro 2742 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2743 depends on KUNIT 2743 depends on KUNIT
2744 default KUNIT_ALL_TESTS 2744 default KUNIT_ALL_TESTS
2745 help 2745 help
2746 Builds unit tests for the is_signed 2746 Builds unit tests for the is_signed_type() macro.
2747 2747
2748 For more information on KUnit and u 2748 For more information on KUnit and unit tests in general please refer
2749 to the KUnit documentation in Docum 2749 to the KUnit documentation in Documentation/dev-tools/kunit/.
2750 2750
2751 If unsure, say N. 2751 If unsure, say N.
2752 2752
2753 config OVERFLOW_KUNIT_TEST 2753 config OVERFLOW_KUNIT_TEST
2754 tristate "Test check_*_overflow() fun 2754 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2755 depends on KUNIT 2755 depends on KUNIT
2756 default KUNIT_ALL_TESTS 2756 default KUNIT_ALL_TESTS
2757 help 2757 help
2758 Builds unit tests for the check_*_o 2758 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2759 related functions. 2759 related functions.
2760 2760
2761 For more information on KUnit and u 2761 For more information on KUnit and unit tests in general please refer
2762 to the KUnit documentation in Docum 2762 to the KUnit documentation in Documentation/dev-tools/kunit/.
2763 2763
2764 If unsure, say N. 2764 If unsure, say N.
2765 2765
2766 config STACKINIT_KUNIT_TEST 2766 config STACKINIT_KUNIT_TEST
2767 tristate "Test level of stack variabl 2767 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2768 depends on KUNIT 2768 depends on KUNIT
2769 default KUNIT_ALL_TESTS 2769 default KUNIT_ALL_TESTS
2770 help 2770 help
2771 Test if the kernel is zero-initiali 2771 Test if the kernel is zero-initializing stack variables and
2772 padding. Coverage is controlled by 2772 padding. Coverage is controlled by compiler flags,
2773 CONFIG_INIT_STACK_ALL_PATTERN, CONF 2773 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2774 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFI 2774 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2775 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYR 2775 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2776 2776
2777 config FORTIFY_KUNIT_TEST 2777 config FORTIFY_KUNIT_TEST
2778 tristate "Test fortified str*() and m 2778 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2779 depends on KUNIT 2779 depends on KUNIT
2780 default KUNIT_ALL_TESTS 2780 default KUNIT_ALL_TESTS
2781 help 2781 help
2782 Builds unit tests for checking inte 2782 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2783 by the str*() and mem*() family of 2783 by the str*() and mem*() family of functions. For testing runtime
2784 traps of FORTIFY_SOURCE, see LKDTM' 2784 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2785 2785
2786 config HW_BREAKPOINT_KUNIT_TEST 2786 config HW_BREAKPOINT_KUNIT_TEST
2787 bool "Test hw_breakpoint constraints 2787 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2788 depends on HAVE_HW_BREAKPOINT 2788 depends on HAVE_HW_BREAKPOINT
2789 depends on KUNIT=y 2789 depends on KUNIT=y
2790 default KUNIT_ALL_TESTS 2790 default KUNIT_ALL_TESTS
2791 help 2791 help
2792 Tests for hw_breakpoint constraints 2792 Tests for hw_breakpoint constraints accounting.
2793 2793
2794 If unsure, say N. 2794 If unsure, say N.
2795 2795
2796 config SIPHASH_KUNIT_TEST 2796 config SIPHASH_KUNIT_TEST
2797 tristate "Perform selftest on siphash 2797 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2798 depends on KUNIT 2798 depends on KUNIT
2799 default KUNIT_ALL_TESTS 2799 default KUNIT_ALL_TESTS
2800 help 2800 help
2801 Enable this option to test the kern 2801 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2802 functions on boot (or module load). 2802 functions on boot (or module load).
2803 2803
2804 This is intended to help people wri 2804 This is intended to help people writing architecture-specific
2805 optimized versions. If unsure, say 2805 optimized versions. If unsure, say N.
2806 2806
2807 config USERCOPY_KUNIT_TEST 2807 config USERCOPY_KUNIT_TEST
2808 tristate "KUnit Test for user/kernel 2808 tristate "KUnit Test for user/kernel boundary protections"
2809 depends on KUNIT 2809 depends on KUNIT
2810 default KUNIT_ALL_TESTS 2810 default KUNIT_ALL_TESTS
2811 help 2811 help
2812 This builds the "usercopy_kunit" mo 2812 This builds the "usercopy_kunit" module that runs sanity checks
2813 on the copy_to/from_user infrastruc 2813 on the copy_to/from_user infrastructure, making sure basic
2814 user/kernel boundary testing is wor 2814 user/kernel boundary testing is working.
2815 2815
2816 config TEST_UDELAY 2816 config TEST_UDELAY
2817 tristate "udelay test driver" 2817 tristate "udelay test driver"
2818 help 2818 help
2819 This builds the "udelay_test" modul 2819 This builds the "udelay_test" module that helps to make sure
2820 that udelay() is working properly. 2820 that udelay() is working properly.
2821 2821
2822 If unsure, say N. 2822 If unsure, say N.
2823 2823
2824 config TEST_STATIC_KEYS 2824 config TEST_STATIC_KEYS
2825 tristate "Test static keys" 2825 tristate "Test static keys"
2826 depends on m 2826 depends on m
2827 help 2827 help
2828 Test the static key interfaces. 2828 Test the static key interfaces.
2829 2829
2830 If unsure, say N. 2830 If unsure, say N.
2831 2831
2832 config TEST_DYNAMIC_DEBUG 2832 config TEST_DYNAMIC_DEBUG
2833 tristate "Test DYNAMIC_DEBUG" 2833 tristate "Test DYNAMIC_DEBUG"
2834 depends on DYNAMIC_DEBUG 2834 depends on DYNAMIC_DEBUG
2835 help 2835 help
2836 This module registers a tracer call 2836 This module registers a tracer callback to count enabled
2837 pr_debugs in a 'do_debugging' funct 2837 pr_debugs in a 'do_debugging' function, then alters their
2838 enablements, calls the function, an 2838 enablements, calls the function, and compares counts.
2839 2839
2840 If unsure, say N. 2840 If unsure, say N.
2841 2841
2842 config TEST_KMOD 2842 config TEST_KMOD
2843 tristate "kmod stress tester" 2843 tristate "kmod stress tester"
2844 depends on m 2844 depends on m
2845 depends on NETDEVICES && NET_CORE && 2845 depends on NETDEVICES && NET_CORE && INET # for TUN
2846 depends on BLOCK 2846 depends on BLOCK
2847 depends on PAGE_SIZE_LESS_THAN_256KB 2847 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2848 select TEST_LKM 2848 select TEST_LKM
2849 select XFS_FS 2849 select XFS_FS
2850 select TUN 2850 select TUN
2851 select BTRFS_FS 2851 select BTRFS_FS
2852 help 2852 help
2853 Test the kernel's module loading me 2853 Test the kernel's module loading mechanism: kmod. kmod implements
2854 support to load modules using the L 2854 support to load modules using the Linux kernel's usermode helper.
2855 This test provides a series of test 2855 This test provides a series of tests against kmod.
2856 2856
2857 Although technically you can either 2857 Although technically you can either build test_kmod as a module or
2858 into the kernel we disallow buildin 2858 into the kernel we disallow building it into the kernel since
2859 it stress tests request_module() an 2859 it stress tests request_module() and this will very likely cause
2860 some issues by taking over precious 2860 some issues by taking over precious threads available from other
2861 module load requests, ultimately th 2861 module load requests, ultimately this could be fatal.
2862 2862
2863 To run tests run: 2863 To run tests run:
2864 2864
2865 tools/testing/selftests/kmod/kmod.s 2865 tools/testing/selftests/kmod/kmod.sh --help
2866 2866
2867 If unsure, say N. 2867 If unsure, say N.
2868 2868
2869 config TEST_DEBUG_VIRTUAL 2869 config TEST_DEBUG_VIRTUAL
2870 tristate "Test CONFIG_DEBUG_VIRTUAL f 2870 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2871 depends on DEBUG_VIRTUAL 2871 depends on DEBUG_VIRTUAL
2872 help 2872 help
2873 Test the kernel's ability to detect 2873 Test the kernel's ability to detect incorrect calls to
2874 virt_to_phys() done against the non 2874 virt_to_phys() done against the non-linear part of the
2875 kernel's virtual address map. 2875 kernel's virtual address map.
2876 2876
2877 If unsure, say N. 2877 If unsure, say N.
2878 2878
2879 config TEST_MEMCAT_P 2879 config TEST_MEMCAT_P
2880 tristate "Test memcat_p() helper func 2880 tristate "Test memcat_p() helper function"
2881 help 2881 help
2882 Test the memcat_p() helper for corr 2882 Test the memcat_p() helper for correctly merging two
2883 pointer arrays together. 2883 pointer arrays together.
2884 2884
2885 If unsure, say N. 2885 If unsure, say N.
2886 2886
2887 config TEST_OBJAGG 2887 config TEST_OBJAGG
2888 tristate "Perform selftest on object 2888 tristate "Perform selftest on object aggreration manager"
2889 default n 2889 default n
2890 depends on OBJAGG 2890 depends on OBJAGG
2891 help 2891 help
2892 Enable this option to test object a 2892 Enable this option to test object aggregation manager on boot
2893 (or module load). 2893 (or module load).
2894 2894
2895 config TEST_MEMINIT 2895 config TEST_MEMINIT
2896 tristate "Test heap/page initializati 2896 tristate "Test heap/page initialization"
2897 help 2897 help
2898 Test if the kernel is zero-initiali 2898 Test if the kernel is zero-initializing heap and page allocations.
2899 This can be useful to test init_on_ 2899 This can be useful to test init_on_alloc and init_on_free features.
2900 2900
2901 If unsure, say N. 2901 If unsure, say N.
2902 2902
2903 config TEST_HMM 2903 config TEST_HMM
2904 tristate "Test HMM (Heterogeneous Mem 2904 tristate "Test HMM (Heterogeneous Memory Management)"
2905 depends on TRANSPARENT_HUGEPAGE 2905 depends on TRANSPARENT_HUGEPAGE
2906 depends on DEVICE_PRIVATE 2906 depends on DEVICE_PRIVATE
2907 select HMM_MIRROR 2907 select HMM_MIRROR
2908 select MMU_NOTIFIER 2908 select MMU_NOTIFIER
2909 help 2909 help
2910 This is a pseudo device driver sole 2910 This is a pseudo device driver solely for testing HMM.
2911 Say M here if you want to build the 2911 Say M here if you want to build the HMM test module.
2912 Doing so will allow you to run tool 2912 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2913 2913
2914 If unsure, say N. 2914 If unsure, say N.
2915 2915
2916 config TEST_FREE_PAGES 2916 config TEST_FREE_PAGES
2917 tristate "Test freeing pages" 2917 tristate "Test freeing pages"
2918 help 2918 help
2919 Test that a memory leak does not oc 2919 Test that a memory leak does not occur due to a race between
2920 freeing a block of pages and a spec 2920 freeing a block of pages and a speculative page reference.
2921 Loading this module is safe if your 2921 Loading this module is safe if your kernel has the bug fixed.
2922 If the bug is not fixed, it will le 2922 If the bug is not fixed, it will leak gigabytes of memory and
2923 probably OOM your system. 2923 probably OOM your system.
2924 2924
2925 config TEST_FPU 2925 config TEST_FPU
2926 tristate "Test floating point operati 2926 tristate "Test floating point operations in kernel space"
2927 depends on ARCH_HAS_KERNEL_FPU_SUPPOR 2927 depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
2928 help 2928 help
2929 Enable this option to add /sys/kern 2929 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2930 which will trigger a sequence of fl 2930 which will trigger a sequence of floating point operations. This is used
2931 for self-testing floating point con 2931 for self-testing floating point control register setting in
2932 kernel_fpu_begin(). 2932 kernel_fpu_begin().
2933 2933
2934 If unsure, say N. 2934 If unsure, say N.
2935 2935
2936 config TEST_CLOCKSOURCE_WATCHDOG 2936 config TEST_CLOCKSOURCE_WATCHDOG
2937 tristate "Test clocksource watchdog i 2937 tristate "Test clocksource watchdog in kernel space"
2938 depends on CLOCKSOURCE_WATCHDOG 2938 depends on CLOCKSOURCE_WATCHDOG
2939 help 2939 help
2940 Enable this option to create a kern 2940 Enable this option to create a kernel module that will trigger
2941 a test of the clocksource watchdog. 2941 a test of the clocksource watchdog. This module may be loaded
2942 via modprobe or insmod in which cas 2942 via modprobe or insmod in which case it will run upon being
2943 loaded, or it may be built in, in w 2943 loaded, or it may be built in, in which case it will run
2944 shortly after boot. 2944 shortly after boot.
2945 2945
2946 If unsure, say N. 2946 If unsure, say N.
2947 2947
2948 config TEST_OBJPOOL 2948 config TEST_OBJPOOL
2949 tristate "Test module for correctness 2949 tristate "Test module for correctness and stress of objpool"
2950 default n 2950 default n
2951 depends on m && DEBUG_KERNEL 2951 depends on m && DEBUG_KERNEL
2952 help 2952 help
2953 This builds the "test_objpool" modu 2953 This builds the "test_objpool" module that should be used for
2954 correctness verification and concur 2954 correctness verification and concurrent testings of objects
2955 allocation and reclamation. 2955 allocation and reclamation.
2956 2956
2957 If unsure, say N. 2957 If unsure, say N.
2958 2958
2959 endif # RUNTIME_TESTING_MENU 2959 endif # RUNTIME_TESTING_MENU
2960 2960
2961 config ARCH_USE_MEMTEST 2961 config ARCH_USE_MEMTEST
2962 bool 2962 bool
2963 help 2963 help
2964 An architecture should select this 2964 An architecture should select this when it uses early_memtest()
2965 during boot process. 2965 during boot process.
2966 2966
2967 config MEMTEST 2967 config MEMTEST
2968 bool "Memtest" 2968 bool "Memtest"
2969 depends on ARCH_USE_MEMTEST 2969 depends on ARCH_USE_MEMTEST
2970 help 2970 help
2971 This option adds a kernel parameter 2971 This option adds a kernel parameter 'memtest', which allows memtest
2972 to be set and executed. 2972 to be set and executed.
2973 memtest=0, mean disabled; -- 2973 memtest=0, mean disabled; -- default
2974 memtest=1, mean do 1 test pat 2974 memtest=1, mean do 1 test pattern;
2975 ... 2975 ...
2976 memtest=17, mean do 17 test p 2976 memtest=17, mean do 17 test patterns.
2977 If you are unsure how to answer thi 2977 If you are unsure how to answer this question, answer N.
2978 2978
2979 2979
2980 2980
2981 config HYPERV_TESTING 2981 config HYPERV_TESTING
2982 bool "Microsoft Hyper-V driver testin 2982 bool "Microsoft Hyper-V driver testing"
2983 default n 2983 default n
2984 depends on HYPERV && DEBUG_FS 2984 depends on HYPERV && DEBUG_FS
2985 help 2985 help
2986 Select this option to enable Hyper- 2986 Select this option to enable Hyper-V vmbus testing.
2987 2987
2988 endmenu # "Kernel Testing and Coverage" 2988 endmenu # "Kernel Testing and Coverage"
2989 2989
2990 menu "Rust hacking" 2990 menu "Rust hacking"
2991 2991
2992 config RUST_DEBUG_ASSERTIONS 2992 config RUST_DEBUG_ASSERTIONS
2993 bool "Debug assertions" 2993 bool "Debug assertions"
2994 depends on RUST 2994 depends on RUST
2995 help 2995 help
2996 Enables rustc's `-Cdebug-assertions 2996 Enables rustc's `-Cdebug-assertions` codegen option.
2997 2997
2998 This flag lets you turn `cfg(debug_ 2998 This flag lets you turn `cfg(debug_assertions)` conditional
2999 compilation on or off. This can be 2999 compilation on or off. This can be used to enable extra debugging
3000 code in development but not in prod 3000 code in development but not in production. For example, it controls
3001 the behavior of the standard librar 3001 the behavior of the standard library's `debug_assert!` macro.
3002 3002
3003 Note that this will apply to all Ru 3003 Note that this will apply to all Rust code, including `core`.
3004 3004
3005 If unsure, say N. 3005 If unsure, say N.
3006 3006
3007 config RUST_OVERFLOW_CHECKS 3007 config RUST_OVERFLOW_CHECKS
3008 bool "Overflow checks" 3008 bool "Overflow checks"
3009 default y 3009 default y
3010 depends on RUST 3010 depends on RUST
3011 help 3011 help
3012 Enables rustc's `-Coverflow-checks` 3012 Enables rustc's `-Coverflow-checks` codegen option.
3013 3013
3014 This flag allows you to control the 3014 This flag allows you to control the behavior of runtime integer
3015 overflow. When overflow-checks are 3015 overflow. When overflow-checks are enabled, a Rust panic will occur
3016 on overflow. 3016 on overflow.
3017 3017
3018 Note that this will apply to all Ru 3018 Note that this will apply to all Rust code, including `core`.
3019 3019
3020 If unsure, say Y. 3020 If unsure, say Y.
3021 3021
3022 config RUST_BUILD_ASSERT_ALLOW 3022 config RUST_BUILD_ASSERT_ALLOW
3023 bool "Allow unoptimized build-time as 3023 bool "Allow unoptimized build-time assertions"
3024 depends on RUST 3024 depends on RUST
3025 help 3025 help
3026 Controls how are `build_error!` and 3026 Controls how are `build_error!` and `build_assert!` handled during build.
3027 3027
3028 If calls to them exist in the binar 3028 If calls to them exist in the binary, it may indicate a violated invariant
3029 or that the optimizer failed to ver 3029 or that the optimizer failed to verify the invariant during compilation.
3030 3030
3031 This should not happen, thus by def 3031 This should not happen, thus by default the build is aborted. However,
3032 as an escape hatch, you can choose 3032 as an escape hatch, you can choose Y here to ignore them during build
3033 and let the check be carried at run 3033 and let the check be carried at runtime (with `panic!` being called if
3034 the check fails). 3034 the check fails).
3035 3035
3036 If unsure, say N. 3036 If unsure, say N.
3037 3037
3038 config RUST_KERNEL_DOCTESTS 3038 config RUST_KERNEL_DOCTESTS
3039 bool "Doctests for the `kernel` crate 3039 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3040 depends on RUST && KUNIT=y 3040 depends on RUST && KUNIT=y
3041 default KUNIT_ALL_TESTS 3041 default KUNIT_ALL_TESTS
3042 help 3042 help
3043 This builds the documentation tests 3043 This builds the documentation tests of the `kernel` crate
3044 as KUnit tests. 3044 as KUnit tests.
3045 3045
3046 For more information on KUnit and u 3046 For more information on KUnit and unit tests in general,
3047 please refer to the KUnit documenta 3047 please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3048 3048
3049 If unsure, say N. 3049 If unsure, say N.
3050 3050
3051 endmenu # "Rust" 3051 endmenu # "Rust"
3052 3052
3053 endmenu # Kernel hacking 3053 endmenu # Kernel hacking
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