1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/fault-inject.h>
3 #include <linux/error-injection.h>
4 #include <linux/debugfs.h>
5 #include <linux/slab.h>
6 #include <linux/mm.h>
7 #include "slab.h"
8
9 static struct {
10 struct fault_attr attr;
11 bool ignore_gfp_reclaim;
12 bool cache_filter;
13 } failslab = {
14 .attr = FAULT_ATTR_INITIALIZER,
15 .ignore_gfp_reclaim = true,
16 .cache_filter = false,
17 };
18
should_failslab(struct kmem_cache * s,gfp_t gfpflags)19 int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
20 {
21 int flags = 0;
22
23 /* No fault-injection for bootstrap cache */
24 if (unlikely(s == kmem_cache))
25 return 0;
26
27 if (gfpflags & __GFP_NOFAIL)
28 return 0;
29
30 if (failslab.ignore_gfp_reclaim &&
31 (gfpflags & __GFP_DIRECT_RECLAIM))
32 return 0;
33
34 if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
35 return 0;
36
37 /*
38 * In some cases, it expects to specify __GFP_NOWARN
39 * to avoid printing any information(not just a warning),
40 * thus avoiding deadlocks. See commit 6b9dbedbe349 for
41 * details.
42 */
43 if (gfpflags & __GFP_NOWARN)
44 flags |= FAULT_NOWARN;
45
46 return should_fail_ex(&failslab.attr, s->object_size, flags) ? -ENOMEM : 0;
47 }
48 ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
49
setup_failslab(char * str)50 static int __init setup_failslab(char *str)
51 {
52 return setup_fault_attr(&failslab.attr, str);
53 }
54 __setup("failslab=", setup_failslab);
55
56 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
failslab_debugfs_init(void)57 static int __init failslab_debugfs_init(void)
58 {
59 struct dentry *dir;
60 umode_t mode = S_IFREG | 0600;
61
62 dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
63 if (IS_ERR(dir))
64 return PTR_ERR(dir);
65
66 debugfs_create_bool("ignore-gfp-wait", mode, dir,
67 &failslab.ignore_gfp_reclaim);
68 debugfs_create_bool("cache-filter", mode, dir,
69 &failslab.cache_filter);
70
71 return 0;
72 }
73
74 late_initcall(failslab_debugfs_init);
75
76 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
77