4f6923fbb3
should_failslab() is a convenient function to hook into for directed
error injection into kmalloc(). However, it is only available if a
config flag is set.
The following BCC script, for example, fails kmalloc() calls after a
btrfs umount:
from bcc import BPF
prog = r"""
BPF_HASH(flag);
#include <linux/mm.h>
int kprobe__btrfs_close_devices(void *ctx) {
u64 key = 1;
flag.update(&key, &key);
return 0;
}
int kprobe__should_failslab(struct pt_regs *ctx) {
u64 key = 1;
u64 *res;
res = flag.lookup(&key);
if (res != 0) {
bpf_override_return(ctx, -ENOMEM);
}
return 0;
}
"""
b = BPF(text=prog)
while 1:
b.kprobe_poll()
This patch refactors the should_failslab implementation so that the
function is always available for error injection, independent of flags.
This change would be similar in nature to commit f5490d3ec921 ("block:
Add should_fail_bio() for bpf error injection").
Link: http://lkml.kernel.org/r/20180222020320.6944-1-hmclauchlan@fb.com
Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Johannes Weiner <jweiner@fb.com>
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
78 lines
1.9 KiB
C
78 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FAULT_INJECT_H
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#define _LINUX_FAULT_INJECT_H
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#ifdef CONFIG_FAULT_INJECTION
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#include <linux/types.h>
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#include <linux/debugfs.h>
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#include <linux/ratelimit.h>
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#include <linux/atomic.h>
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/*
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* For explanation of the elements of this struct, see
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* Documentation/fault-injection/fault-injection.txt
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*/
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struct fault_attr {
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unsigned long probability;
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unsigned long interval;
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atomic_t times;
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atomic_t space;
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unsigned long verbose;
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bool task_filter;
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unsigned long stacktrace_depth;
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unsigned long require_start;
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unsigned long require_end;
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unsigned long reject_start;
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unsigned long reject_end;
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unsigned long count;
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struct ratelimit_state ratelimit_state;
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struct dentry *dname;
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};
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#define FAULT_ATTR_INITIALIZER { \
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.interval = 1, \
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.times = ATOMIC_INIT(1), \
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.require_end = ULONG_MAX, \
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.stacktrace_depth = 32, \
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.ratelimit_state = RATELIMIT_STATE_INIT_DISABLED, \
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.verbose = 2, \
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.dname = NULL, \
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}
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#define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER
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int setup_fault_attr(struct fault_attr *attr, char *str);
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bool should_fail(struct fault_attr *attr, ssize_t size);
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#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
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struct dentry *fault_create_debugfs_attr(const char *name,
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struct dentry *parent, struct fault_attr *attr);
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#else /* CONFIG_FAULT_INJECTION_DEBUG_FS */
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static inline struct dentry *fault_create_debugfs_attr(const char *name,
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struct dentry *parent, struct fault_attr *attr)
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{
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return ERR_PTR(-ENODEV);
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}
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#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
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#endif /* CONFIG_FAULT_INJECTION */
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struct kmem_cache;
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int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
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#ifdef CONFIG_FAILSLAB
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extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags);
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#else
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static inline bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
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{
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return false;
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}
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#endif /* CONFIG_FAILSLAB */
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#endif /* _LINUX_FAULT_INJECT_H */
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