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