Commit 21e25205 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Christian Brauner
Browse files

pidfd: don't do_notify_pidfd() if !thread_group_empty() 



do_notify_pidfd() makes no sense until the whole thread group exits, change
do_notify_parent() to check thread_group_empty().

This avoids the unnecessary do_notify_pidfd() when tsk is not a leader, or
it exits before other threads, or it has a ptraced EXIT_ZOMBIE sub-thread.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20240127132407.GA29136@redhat.com


Reviewed-by: default avatarTycho Andersen <tandersen@netflix.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent cdefbf23

kernel/signal.c

+5 −3
Original line number Diff line number Diff line
@@ -2050,8 +2050,10 @@ bool do_notify_parent(struct task_struct *tsk, int sig) 


	WARN_ON_ONCE(!tsk->ptrace &&

	       (tsk->group_leader != tsk || !thread_group_empty(tsk)));



	/* Wake up all pidfd waiters */

	/*

	 * tsk is a group leader and has no threads, wake up the pidfd waiters.

	 */

	if (thread_group_empty(tsk))

		do_notify_pidfd(tsk);



	if (sig != SIGCHLD) {