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authorTejun Heo <tj@kernel.org>2011-06-02 11:14:00 +0200
committerOleg Nesterov <oleg@redhat.com>2011-06-04 18:17:11 +0200
commit62c124ff3bcdb414af635c2bf822c9e4f2a5abfa (patch)
tree5d279211e098d24245d49e394d84aa8cfdb6f277 /kernel/signal.c
parent7dd3db54e77d21eb95e145f19ba53f68250d0e73 (diff)
downloadlwn-62c124ff3bcdb414af635c2bf822c9e4f2a5abfa.tar.gz
lwn-62c124ff3bcdb414af635c2bf822c9e4f2a5abfa.zip
ptrace: use bit_waitqueue for TRAPPING instead of wait_chldexit
ptracer->signal->wait_chldexit was used to wait for TRAPPING; however, ->wait_chldexit was already complicated with waker-side filtering without adding TRAPPING wait on top of it. Also, it unnecessarily made TRAPPING clearing depend on the current ptrace relationship - if the ptracee is detached, wakeup is lost. There is no reason to use signal->wait_chldexit here. We're just waiting for JOBCTL_TRAPPING bit to clear and given the relatively infrequent use of ptrace, bit_waitqueue can serve it perfectly. This patch makes JOBCTL_TRAPPING wait use bit_waitqueue instead of signal->wait_chldexit. -v2: Use JOBCTL_*_BIT macros instead of ilog2() as suggested by Linus. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 9ab91c516c3f..172a4c79f12c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -272,8 +272,7 @@ static void task_clear_jobctl_trapping(struct task_struct *task)
{
if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
task->jobctl &= ~JOBCTL_TRAPPING;
- __wake_up_sync_key(&task->parent->signal->wait_chldexit,
- TASK_UNINTERRUPTIBLE, 1, task);
+ wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
}
}