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| author | Mandeep Singh Baines <msb@chromium.org> | 2012-01-03 14:41:13 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-03 16:14:32 -0800 |
| commit | f9fab10bbd768b0e5254e53a4a8477a94bfc4b96 (patch) | |
| tree | 7f4efb5c46582765c12249f652a8975a1956f781 /kernel/hung_task.c | |
| parent | 30e053248da178cf6154bb7e950dc8713567e3fa (diff) | |
| download | linux-f9fab10bbd768b0e5254e53a4a8477a94bfc4b96.tar.gz | |
hung_task: fix false positive during vfork
vfork parent uninterruptibly and unkillably waits for its child to exec/exit. This wait is of unbounded length. Ignore such waits in the hung_task detector. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Reported-by: Sasha Levin <levinsasha928@gmail.com> LKML-Reference: <1325344394.28904.43.camel@lappy> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Kacur <jkacur@redhat.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/hung_task.c')
| -rw-r--r-- | kernel/hung_task.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 8b1748d0172c..2e48ec0c2e91 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -74,11 +74,17 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) /* * Ensure the task is not frozen. - * Also, when a freshly created task is scheduled once, changes - * its state to TASK_UNINTERRUPTIBLE without having ever been - * switched out once, it musn't be checked. + * Also, skip vfork and any other user process that freezer should skip. */ - if (unlikely(t->flags & PF_FROZEN || !switch_count)) + if (unlikely(t->flags & (PF_FROZEN | PF_FREEZER_SKIP))) + return; + + /* + * When a freshly created task is scheduled once, changes its state to + * TASK_UNINTERRUPTIBLE without having ever been switched out once, it + * musn't be checked. + */ + if (unlikely(!switch_count)) return; if (switch_count != t->last_switch_count) { |