blk_mq_quiesce_queue() callers, e.g. elevator_switch_mq(), assume
that no .queue_rq() calls occur while switching to another I/O
scheduler. This patch fixes the following kernel crash if another
I/O scheduler than "none" is the default scheduler:
general protection fault: 0000 [#1] SMP
RIP: 0010:__lock_acquire+0xfe/0x1280
Call Trace:
lock_acquire+0xd5/0x1c0
_raw_spin_lock+0x2a/0x40
dd_dispatch_request+0x29/0x1e0
blk_mq_sched_dispatch_requests+0x139/0x190
__blk_mq_run_hw_queue+0x12d/0x1c0
blk_mq_run_work_fn+0xd/0x10
process_one_work+0x206/0x6a0
worker_thread+0x49/0x4a0
kthread+0x107/0x140
ret_from_fork+0x2e/0x40
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
block/blk-mq.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b75ef2392db7..3b3420f76b5a 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1224,8 +1224,9 @@ EXPORT_SYMBOL(blk_mq_queue_stopped);
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
{
- cancel_work(&hctx->run_work);
- cancel_delayed_work(&hctx->delay_work);
+ cancel_work_sync(&hctx->run_work);
+ cancel_delayed_work_sync(&hctx->delay_work);
+ cancel_delayed_work_sync(&hctx->delayed_run_work);
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
--
2.12.2