From: Oleg Nesterov Date: Wed, 30 Apr 2008 07:52:58 +0000 (-0700) Subject: signals: handle_stop_signal: don't worry about SIGKILL X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=34c8f07b9ac499a807918eda377193a55f64f8df;p=linux-beck.git signals: handle_stop_signal: don't worry about SIGKILL handle_stop_signal() clears SIGNAL_STOP_DEQUEUED when sig == SIGKILL. Remove this nasty special case. It was needed to prevent the race with group stop and exit caused by thread-specific SIGKILL. Now that we use complete_signal() for private signals too this is not needed, complete_signal() will notice SIGKILL and abort the soon-to-begin group stop. Except: the target thread is dead (has PF_EXITING). But in that case we should not just clear SIGNAL_STOP_DEQUEUED and nothing more. We should either kill the whole thread group, or silently ignore the signal. I suspect we are not right wrt zombie leaders, but this is another issue which and should be fixed separately. Note that this check can't abort the group stop if it was already started/finished, this check only adds a subtle side effect if we race with the thread which has already dequeued sig_kernel_stop() signal and temporary released ->siglock. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/signal.c b/kernel/signal.c index d52a1fe921fa..0a873279393c 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -643,12 +643,6 @@ static void handle_stop_signal(int sig, struct task_struct *p) */ signal->flags &= ~SIGNAL_STOP_DEQUEUED; } - } else if (sig == SIGKILL) { - /* - * Make sure that any pending stop signal already dequeued - * is undone by the wakeup for SIGKILL. - */ - signal->flags &= ~SIGNAL_STOP_DEQUEUED; } }