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Commit 1406f2d3 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

lock_task_sighand: add rcu lock/unlock 



Most of the callers of lock_task_sighand() doesn't actually need rcu_lock().
lock_task_sighand() needs it only to safely play with tsk->sighand, it can
take the lock itself.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bfc4b089

kernel/signal.c

+2 −3
Original line number Diff line number Diff line
@@ -971,13 +971,11 @@ int __fatal_signal_pending(struct task_struct *tsk) 
}

EXPORT_SYMBOL(__fatal_signal_pending);



/*

 * Must be called under rcu_read_lock() or with tasklist_lock read-held.

 */

struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)

{

	struct sighand_struct *sighand;



	rcu_read_lock();

	for (;;) {

		sighand = rcu_dereference(tsk->sighand);

		if (unlikely(sighand == NULL))
@@ -988,6 +986,7 @@ struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long 
			break;

		spin_unlock_irqrestore(&sighand->siglock, *flags);

	}

	rcu_read_unlock();



	return sighand;

}