diff options
| author | Tejun Heo <tj@kernel.org> | 2011-06-02 11:14:00 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2011-06-04 18:17:11 +0200 |
| commit | 62c124ff3bcdb414af635c2bf822c9e4f2a5abfa (patch) | |
| tree | 5d279211e098d24245d49e394d84aa8cfdb6f277 /kernel | |
| parent | 7dd3db54e77d21eb95e145f19ba53f68250d0e73 (diff) | |
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')
| -rw-r--r-- | kernel/ptrace.c | 10 | ||||
| -rw-r--r-- | kernel/signal.c | 3 |
2 files changed, 9 insertions, 4 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 0c37d999c8b..7f05f3a1267 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -25,6 +25,12 @@ #include <linux/hw_breakpoint.h> +static int ptrace_trapping_sleep_fn(void *flags) +{ + schedule(); + return 0; +} + /* * ptrace a task: make the debugger its new parent and * move it to the ptrace list. @@ -270,8 +276,8 @@ unlock_creds: mutex_unlock(&task->signal->cred_guard_mutex); out: if (!retval) - wait_event(current->signal->wait_chldexit, - !(task->jobctl & JOBCTL_TRAPPING)); + wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, + ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE); return retval; } diff --git a/kernel/signal.c b/kernel/signal.c index 9ab91c516c3..172a4c79f12 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); } } |