path: root/lib/fault-inject.c
diff options
authorAkinobu Mita <akinobu.mita@gmail.com>2017-07-14 14:49:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-14 15:05:13 -0700
commit1203c8e6fb0aa1e9c39d2323607a74c3adc34fd8 (patch)
tree67fc0c8911aec1b7c4bfdfc90305c2ff72b081a0 /lib/fault-inject.c
parentbfc740938d151001cb1158580796f8f3be3bf0c1 (diff)
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')
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;

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