From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Tue, 29 May 2012 09:18:44 +0000 (+0200)
Subject: spinlock: Indicate that a lockup is only suspected
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=8a173b1476d126674104c7c5c6cef0bcd824b001;p=deliverable%2Flinux.git

spinlock: Indicate that a lockup is only suspected

On an over-committed KVM system we got a:

  "BUG: spinlock lockup on CPU#2, swapper/2/0"

message on the heavily contended virtio blk spinlock.

While we might want to reconsider the locking of virtio-blk
(lock is held while switching to the host) this patch tries to
make the message clearer: the lockup is only suspected.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1338283124-7063-1-git-send-email-borntraeger@de.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/lib/spinlock_debug.c b/lib/spinlock_debug.c
index d0ec4f3d1593..e91fbc23fff1 100644
--- a/lib/spinlock_debug.c
+++ b/lib/spinlock_debug.c
@@ -118,7 +118,7 @@ static void __spin_lock_debug(raw_spinlock_t *lock)
 		/* lockup suspected: */
 		if (print_once) {
 			print_once = 0;
-			spin_dump(lock, "lockup");
+			spin_dump(lock, "lockup suspected");
 #ifdef CONFIG_SMP
 			trigger_all_cpu_backtrace();
 #endif