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| author | Akinobu Mita <akinobu.mita@gmail.com> | 2017-07-14 14:49:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-14 15:05:13 -0700 |
| commit | 1203c8e6fb0aa1e9c39d2323607a74c3adc34fd8 (patch) | |
| tree | 67fc0c8911aec1b7c4bfdfc90305c2ff72b081a0 /lib/fault-inject.c | |
| parent | bfc740938d151001cb1158580796f8f3be3bf0c1 (diff) | |
| download | lwn-1203c8e6fb0aa1e9c39d2323607a74c3adc34fd8.tar.gz lwn-1203c8e6fb0aa1e9c39d2323607a74c3adc34fd8.zip | |
fault-inject: simplify access check for fail-nth
The fail-nth file is created with 0666 and the access is permitted if
and only if the task is current.
This file is owned by the currnet user. So we can create it with 0644
and allow the owner to write it. This enables to watch the status of
task->fail_nth from another processes.
[akinobu.mita@gmail.com: don't convert unsigned type value as signed int]
Link: http://lkml.kernel.org/r/1492444483-9239-1-git-send-email-akinobu.mita@gmail.com
[akinobu.mita@gmail.com: avoid unwanted data race to task->fail_nth]
Link: http://lkml.kernel.org/r/1499962492-8931-1-git-send-email-akinobu.mita@gmail.com
Link: http://lkml.kernel.org/r/1491490561-10485-5-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/fault-inject.c')
| -rw-r--r-- | lib/fault-inject.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 09ac73c177fd..7d315fdb9f13 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -107,9 +107,12 @@ static inline bool fail_stacktrace(struct fault_attr *attr) bool should_fail(struct fault_attr *attr, ssize_t size) { - if (in_task() && current->fail_nth) { - if (--current->fail_nth == 0) + if (in_task()) { + unsigned int fail_nth = READ_ONCE(current->fail_nth); + + if (fail_nth && !WRITE_ONCE(current->fail_nth, fail_nth - 1)) goto fail; + return false; } |