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authorHeiko Carstens <heiko.carstens@de.ibm.com>2016-04-13 11:05:20 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-04-15 18:01:48 +0200
commit8497695243f70fd19ed6cf28b63584f1b608b5f9 (patch)
tree4e7dd1e66cdb04771e40ea0dd18f92c9d3d0fc8b /arch/s390/lib
parent1378a683443753923eb22d01ce322e92a383ba8a (diff)
s390/spinlock: avoid yield to non existent cpu
arch_spin_lock_wait_flags() checks if a spinlock is not held before trying a compare and swap instruction. If the lock is unlocked it tries the compare and swap instruction, however if a different cpu grabbed the lock in the meantime the instruction will fail as expected. Subsequently the arch_spin_lock_wait_flags() incorrectly tries to figure out if the cpu that holds the lock is running. However it is using the wrong cpu number for this (-1) and then will also yield the current cpu to the wrong cpu. Fix this by adding a missing continue statement. Fixes: 470ada6b1a1d ("s390/spinlock: refactor arch_spin_lock_wait[_flags]") Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/lib')
-rw-r--r--arch/s390/lib/spinlock.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index d4549c964589..e5f50a7d2f4e 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -105,6 +105,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
if (_raw_compare_and_swap(&lp->lock, 0, cpu))
return;
local_irq_restore(flags);
+ continue;
}
/* Check if the lock owner is running. */
if (first_diag && cpu_is_preempted(~owner)) {

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