Unverified Commit 33be3ffd authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "exit: change the release_task() paths to call flush_sigqueue() lockless" 

Oleg Nesterov <oleg@redhat.com> says:

Change the release_task() paths to call flush_sigqueue() lockless.

* patches from https://lore.kernel.org/r/20250206152244.GA14609@redhat.com:
  exit: kill the pointless __exit_signal()->clear_tsk_thread_flag(TIF_SIGPENDING)
  exit: change the release_task() paths to call flush_sigqueue() lockless

Link: https://lore.kernel.org/r/20250206152244.GA14609@redhat.com


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 2014c95a 43966114

kernel/exit.c

+11 −9
Original line number Diff line number Diff line
@@ -200,21 +200,13 @@ static void __exit_signal(struct task_struct *tsk) 
	__unhash_process(tsk, group_dead);

	write_sequnlock(&sig->stats_lock);



	/*

	 * Do this under ->siglock, we can race with another thread

	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.

	 */

	flush_sigqueue(&tsk->pending);

	tsk->sighand = NULL;

	spin_unlock(&sighand->siglock);



	__cleanup_sighand(sighand);

	clear_tsk_thread_flag(tsk, TIF_SIGPENDING);

	if (group_dead) {

		flush_sigqueue(&sig->shared_pending);

	if (group_dead)

		tty_kref_put(tty);

}

}



static void delayed_put_task_struct(struct rcu_head *rhp)

{
@@ -279,6 +271,16 @@ void release_task(struct task_struct *p) 
	proc_flush_pid(thread_pid);

	put_pid(thread_pid);

	release_thread(p);

	/*

	 * This task was already removed from the process/thread/pid lists

	 * and lock_task_sighand(p) can't succeed. Nobody else can touch

	 * ->pending or, if group dead, signal->shared_pending. We can call

	 * flush_sigqueue() lockless.

	 */

	flush_sigqueue(&p->pending);

	if (thread_group_leader(p))

		flush_sigqueue(&p->signal->shared_pending);



	put_task_struct_rcu_user(p);



	p = leader;