1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
5 */
6 #include <linux/sched/debug.h>
7 #include <linux/kallsyms.h>
8 #include <linux/kprobes.h>
9 #include <linux/uaccess.h>
10 #include <linux/hardirq.h>
11 #include <linux/kdebug.h>
12 #include <linux/export.h>
13 #include <linux/ptrace.h>
14 #include <linux/kexec.h>
15 #include <linux/sysfs.h>
16 #include <linux/bug.h>
17 #include <linux/nmi.h>
18
19 #include <asm/stacktrace.h>
20
21 const char *stack_type_name(enum stack_type type)
22 {
23 if (type == STACK_TYPE_IRQ)
24 return "IRQ";
25
26 if (type == STACK_TYPE_SOFTIRQ)
27 return "SOFTIRQ";
28
29 if (type == STACK_TYPE_ENTRY)
30 return "ENTRY_TRAMPOLINE";
31
32 if (type == STACK_TYPE_EXCEPTION)
33 return "#DF";
34
35 return NULL;
36 }
37
38 static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
39 {
40 unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.hardirq_stack_ptr);
41 unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
42
43 /*
44 * This is a software stack, so 'end' can be a valid stack pointer.
45 * It just means the stack is empty.
46 */
47 if (stack < begin || stack > end)
48 return false;
49
50 info->type = STACK_TYPE_IRQ;
51 info->begin = begin;
52 info->end = end;
53
54 /*
55 * See irq_32.c -- the next stack pointer is stored at the beginning of
56 * the stack.
57 */
58 info->next_sp = (unsigned long *)*begin;
59
60 return true;
61 }
62
63 static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
64 {
65 unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.softirq_stack_ptr);
66 unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
67
68 /*
69 * This is a software stack, so 'end' can be a valid stack pointer.
70 * It just means the stack is empty.
71 */
72 if (stack < begin || stack > end)
73 return false;
74
75 info->type = STACK_TYPE_SOFTIRQ;
76 info->begin = begin;
77 info->end = end;
78
79 /*
80 * The next stack pointer is stored at the beginning of the stack.
81 * See irq_32.c.
82 */
83 info->next_sp = (unsigned long *)*begin;
84
85 return true;
86 }
87
88 static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
89 {
90 struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id());
91 struct doublefault_stack *ss = &cea->doublefault_stack;
92
93 void *begin = ss->stack;
94 void *end = begin + sizeof(ss->stack);
95
96 if ((void *)stack < begin || (void *)stack >= end)
97 return false;
98
99 info->type = STACK_TYPE_EXCEPTION;
100 info->begin = begin;
101 info->end = end;
102 info->next_sp = (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp);
103
104 return true;
105 }
106
107
108 int get_stack_info(unsigned long *stack, struct task_struct *task,
109 struct stack_info *info, unsigned long *visit_mask)
110 {
111 if (!stack)
112 goto unknown;
113
114 task = task ? : current;
115
116 if (in_task_stack(stack, task, info))
117 goto recursion_check;
118
119 if (task != current)
120 goto unknown;
121
122 if (in_entry_stack(stack, info))
123 goto recursion_check;
124
125 if (in_hardirq_stack(stack, info))
126 goto recursion_check;
127
128 if (in_softirq_stack(stack, info))
129 goto recursion_check;
130
131 if (in_doublefault_stack(stack, info))
132 goto recursion_check;
133
134 goto unknown;
135
136 recursion_check:
137 /*
138 * Make sure we don't iterate through any given stack more than once.
139 * If it comes up a second time then there's something wrong going on:
140 * just break out and report an unknown stack type.
141 */
142 if (visit_mask) {
143 if (*visit_mask & (1UL << info->type)) {
144 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
145 goto unknown;
146 }
147 *visit_mask |= 1UL << info->type;
148 }
149
150 return 0;
151
152 unknown:
153 info->type = STACK_TYPE_UNKNOWN;
154 return -EINVAL;
155 }
156
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