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Commit 6ca25b55 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

kill_pid_info: don't take now unneeded tasklist_lock 



Previously handle_stop_signal(SIGCONT) could drop ->siglock.  That is why
kill_pid_info(SIGCONT) takes tasklist_lock to make sure the target task can't
go away after unlock.  Not needed now.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e4420551

include/linux/signal.h

+0 −2
Original line number Diff line number Diff line
@@ -362,8 +362,6 @@ int unhandled_signal(struct task_struct *tsk, int sig); 
#define sig_kernel_stop(sig) \

	(((sig) < SIGRTMIN) && siginmask(sig, SIG_KERNEL_STOP_MASK))



#define sig_needs_tasklist(sig)	((sig) == SIGCONT)



#define sig_user_defined(t, signr) \

	(((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_DFL) &&	\

	 ((t)->sighand->action[(signr)-1].sa.sa_handler != SIG_IGN))

kernel/signal.c

+1 −6
Original line number Diff line number Diff line
@@ -1039,9 +1039,6 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) 
	struct task_struct *p;



	rcu_read_lock();

	if (unlikely(sig_needs_tasklist(sig)))

		read_lock(&tasklist_lock);



retry:

	p = pid_task(pid, PIDTYPE_PID);

	if (p) {
@@ -1055,10 +1052,8 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) 
			 */

			goto retry;

	}



	if (unlikely(sig_needs_tasklist(sig)))

		read_unlock(&tasklist_lock);

	rcu_read_unlock();



	return error;

}