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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-10 08:30:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-10 08:30:35 -0700
commita8a4021b776b4475e8a4657185a718cdfc07b88c (patch)
tree54a1c6a013247ea164351b156bf1cd8feaeeed56 /kernel
parent3ca24ce9ff764bc27bceb9b2fd8ece74846c3fd3 (diff)
parent59dc6f3c6d81c0c4379025c4eb56919391d62b67 (diff)
downloadlinux-a8a4021b776b4475e8a4657185a718cdfc07b88c.tar.bz2
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core fixes from Thomas Gleixner: "A small set of core updates: - Make objtool cope with GCC8 oddities some more - Remove a stale local_irq_save/restore sequence in the signal code along with the stale comment in the RCU code. The underlying issue which led to this has been solved long time ago, but nobody cared to cleanup the hackarounds" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: signal: Remove no longer required irqsave/restore rcu: Update documentation of rcu_read_unlock() objtool: Fix GCC 8 cold subfunction detection for aliased functions
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c24
1 files changed, 7 insertions, 17 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 0f865d67415d..8d8a940422a8 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1244,19 +1244,12 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
{
struct sighand_struct *sighand;
+ rcu_read_lock();
for (;;) {
- /*
- * Disable interrupts early to avoid deadlocks.
- * See rcu_read_unlock() comment header for details.
- */
- local_irq_save(*flags);
- rcu_read_lock();
sighand = rcu_dereference(tsk->sighand);
- if (unlikely(sighand == NULL)) {
- rcu_read_unlock();
- local_irq_restore(*flags);
+ if (unlikely(sighand == NULL))
break;
- }
+
/*
* This sighand can be already freed and even reused, but
* we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
@@ -1268,15 +1261,12 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
* __exit_signal(). In the latter case the next iteration
* must see ->sighand == NULL.
*/
- spin_lock(&sighand->siglock);
- if (likely(sighand == tsk->sighand)) {
- rcu_read_unlock();
+ spin_lock_irqsave(&sighand->siglock, *flags);
+ if (likely(sighand == tsk->sighand))
break;
- }
- spin_unlock(&sighand->siglock);
- rcu_read_unlock();
- local_irq_restore(*flags);
+ spin_unlock_irqrestore(&sighand->siglock, *flags);
}
+ rcu_read_unlock();
return sighand;
}