The comment above utrace_wakeup:
* Called with @utrace->lock held and @utrace->stopped set.
Yes. This means the task can't go away, it should at least take
utrace->lock first. No need to use lock_task_sighand().
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
kernel/utrace.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
--- __UTRACE/kernel/utrace.c~6_WAKEUP_SIGLOCK 2009-09-09 00:29:21.000000000
+0200
+++ __UTRACE/kernel/utrace.c 2009-09-09 01:29:02.000000000 +0200
@@ -657,13 +657,9 @@ static bool utrace_do_stop(struct task_s
*/
static void utrace_wakeup(struct task_struct *target, struct utrace *utrace)
{
- unsigned long irqflags;
-
utrace->stopped = 0;
- if (!lock_task_sighand(target, &irqflags))
- return;
-
+ spin_lock_irq(&target->sighand->siglock);
if (likely(task_is_stopped_or_traced(target))) {
if (target->signal->flags & SIGNAL_STOP_STOPPED ||
target->signal->group_stop_count)
@@ -671,8 +667,7 @@ static void utrace_wakeup(struct task_st
else
wake_up_state(target, __TASK_STOPPED | __TASK_TRACED);
}
-
- unlock_task_sighand(target, &irqflags);
+ spin_unlock_irq(&target->sighand->siglock);
}
/*
