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authorLinus Torvalds <torvalds@linux-foundation.org>2015-08-14 10:45:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-08-14 10:45:23 -0700
commit5e5013c6b5150b8009d980d72495a55b79bf5134 (patch)
tree72be7a1f1a5473285c15d76eaaa78aa8cfaead8f /kernel
parentc679765416705db4788902d74ca8d5edcd4cb816 (diff)
parentcba77f03f2c7b6cc0b0a44a3c679e0abade7da62 (diff)
downloadlinux-5e5013c6b5150b8009d980d72495a55b79bf5134.tar.bz2
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Ingo Molnar: "A single fix for a locking self-test crash" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/pvqspinlock: Fix kernel panic in locking-selftest
Diffstat (limited to 'kernel')
-rw-r--r--kernel/locking/qspinlock_paravirt.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 04ab18151cc8..df19ae4debd0 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -4,6 +4,7 @@
#include <linux/hash.h>
#include <linux/bootmem.h>
+#include <linux/debug_locks.h>
/*
* Implement paravirt qspinlocks; the general idea is to halt the vcpus instead
@@ -286,15 +287,23 @@ __visible void __pv_queued_spin_unlock(struct qspinlock *lock)
{
struct __qspinlock *l = (void *)lock;
struct pv_node *node;
+ u8 lockval = cmpxchg(&l->locked, _Q_LOCKED_VAL, 0);
/*
* We must not unlock if SLOW, because in that case we must first
* unhash. Otherwise it would be possible to have multiple @lock
* entries, which would be BAD.
*/
- if (likely(cmpxchg(&l->locked, _Q_LOCKED_VAL, 0) == _Q_LOCKED_VAL))
+ if (likely(lockval == _Q_LOCKED_VAL))
return;
+ if (unlikely(lockval != _Q_SLOW_VAL)) {
+ if (debug_locks_silent)
+ return;
+ WARN(1, "pvqspinlock: lock %p has corrupted value 0x%x!\n", lock, atomic_read(&lock->val));
+ return;
+ }
+
/*
* Since the above failed to release, this must be the SLOW path.
* Therefore start by looking up the blocked node and unhashing it.