linux-stable/include/linux/fault-inject.h
Howard McLauchlan 4f6923fbb3 mm: make should_failslab always available for fault injection
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>
2018-04-05 21:36:26 -07:00

77 lines
1.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FAULT_INJECT_H
#define _LINUX_FAULT_INJECT_H
#ifdef CONFIG_FAULT_INJECTION
#include <linux/types.h>
#include <linux/debugfs.h>
#include <linux/ratelimit.h>
#include <linux/atomic.h>
/*
* For explanation of the elements of this struct, see
* Documentation/fault-injection/fault-injection.txt
*/
struct fault_attr {
unsigned long probability;
unsigned long interval;
atomic_t times;
atomic_t space;
unsigned long verbose;
bool task_filter;
unsigned long stacktrace_depth;
unsigned long require_start;
unsigned long require_end;
unsigned long reject_start;
unsigned long reject_end;
unsigned long count;
struct ratelimit_state ratelimit_state;
struct dentry *dname;
};
#define FAULT_ATTR_INITIALIZER { \
.interval = 1, \
.times = ATOMIC_INIT(1), \
.require_end = ULONG_MAX, \
.stacktrace_depth = 32, \
.ratelimit_state = RATELIMIT_STATE_INIT_DISABLED, \
.verbose = 2, \
.dname = NULL, \
}
#define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER
int setup_fault_attr(struct fault_attr *attr, char *str);
bool should_fail(struct fault_attr *attr, ssize_t size);
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
struct dentry *fault_create_debugfs_attr(const char *name,
struct dentry *parent, struct fault_attr *attr);
#else /* CONFIG_FAULT_INJECTION_DEBUG_FS */
static inline struct dentry *fault_create_debugfs_attr(const char *name,
struct dentry *parent, struct fault_attr *attr)
{
return ERR_PTR(-ENODEV);
}
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
#endif /* CONFIG_FAULT_INJECTION */
struct kmem_cache;
int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
#ifdef CONFIG_FAILSLAB
extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags);
#else
static inline bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
{
return false;
}
#endif /* CONFIG_FAILSLAB */
#endif /* _LINUX_FAULT_INJECT_H */