dm: add cond_resched() to dm_wq_requeue_work()

commit f77692d65d54665d81815349cc727baa85e8b71d upstream.

Otherwise the while() loop in dm_wq_requeue_work() can result in a
"dead loop" on systems that have preemption disabled. This is
particularly problematic on single cpu systems.

Fixes: 8b211aaccb915 ("dm: add two stage requeue mechanism")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 212441671554c762e4fb61536528fe328b5b290c..d727ed9cd623fe99da97d597b5d0a60750df4209 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1020,6 +1020,7 @@ static void dm_wq_requeue_work(struct work_struct *work)
                io->next = NULL;
                __dm_io_complete(io, false);
                io = next;
+               cond_resched();
        }
 }