1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/fault-inject.h>
3 #include <linux/error-injection.h>
4 #include <linux/slab.h>
5 #include <linux/mm.h>
6 #include "slab.h"
7
8 static struct {
9 struct fault_attr attr;
10 bool ignore_gfp_reclaim;
11 bool cache_filter;
12 } failslab = {
13 .attr = FAULT_ATTR_INITIALIZER,
14 .ignore_gfp_reclaim = true,
15 .cache_filter = false,
16 };
17
18 int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
19 {
20 int flags = 0;
21
22 /* No fault-injection for bootstrap cache */
23 if (unlikely(s == kmem_cache))
24 return 0;
25
26 if (gfpflags & __GFP_NOFAIL)
27 return 0;
28
29 if (failslab.ignore_gfp_reclaim &&
30 (gfpflags & __GFP_DIRECT_RECLAIM))
31 return 0;
32
33 if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
34 return 0;
35
36 /*
37 * In some cases, it expects to specify __GFP_NOWARN
38 * to avoid printing any information(not just a warning),
39 * thus avoiding deadlocks. See commit 6b9dbedbe349 for
40 * details.
41 */
42 if (gfpflags & __GFP_NOWARN)
43 flags |= FAULT_NOWARN;
44
45 return should_fail_ex(&failslab.attr, s->object_size, flags) ? -ENOMEM : 0;
46 }
47 ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
48
49 static int __init setup_failslab(char *str)
50 {
51 return setup_fault_attr(&failslab.attr, str);
52 }
53 __setup("failslab=", setup_failslab);
54
55 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
56 static int __init failslab_debugfs_init(void)
57 {
58 struct dentry *dir;
59 umode_t mode = S_IFREG | 0600;
60
61 dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
62 if (IS_ERR(dir))
63 return PTR_ERR(dir);
64
65 debugfs_create_bool("ignore-gfp-wait", mode, dir,
66 &failslab.ignore_gfp_reclaim);
67 debugfs_create_bool("cache-filter", mode, dir,
68 &failslab.cache_filter);
69
70 return 0;
71 }
72
73 late_initcall(failslab_debugfs_init);
74
75 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
76
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