On Tue, 2017-10-17 at 09:55 +0800, chenxiang (M) wrote:
> I find there is a race between blk_cleanup_queue and blk_timeout_work 

Thanks for the detailed report. Would it be possible to test the patch below
(applies on top of 
https://github.com/bvanassche/linux/tree/blk-mq-pm-2017-10-18-v10)?

Thanks,

Bart.


Subject: [PATCH] block: Fix race between blk_cleanup_queue() and timeout 
handling

Make sure that if the timeout timer fires after a queue has been
marked "dying" that the affected requests are finished.

Reported-by: chenxiang (M) <chenxian...@hisilicon.com>
Signed-off-by: Bart Van Assche <bart.vanass...@wdc.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Hannes Reinecke <h...@suse.com>
Cc: Ming Lei <ming....@redhat.com>
Cc: Johannes Thumshirn <jthumsh...@suse.de>
---
 block/blk-core.c    | 1 +
 block/blk-timeout.c | 3 ---
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 4fc9d6d44edd..16f2aa73696e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -333,6 +333,7 @@ EXPORT_SYMBOL(blk_stop_queue);
 void blk_sync_queue(struct request_queue *q)
 {
        del_timer_sync(&q->timeout);
+       cancel_work_sync(&q->timeout_work);
 
        if (q->mq_ops) {
                struct blk_mq_hw_ctx *hctx;
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 1eba71486716..764ecf9aeb30 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -134,8 +134,6 @@ void blk_timeout_work(struct work_struct *work)
        struct request *rq, *tmp;
        int next_set = 0;
 
-       if (blk_queue_enter(q, BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT))
-               return;
        spin_lock_irqsave(q->queue_lock, flags);
 
        list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
@@ -145,7 +143,6 @@ void blk_timeout_work(struct work_struct *work)
                mod_timer(&q->timeout, round_jiffies_up(next));
 
        spin_unlock_irqrestore(q->queue_lock, flags);
-       blk_queue_exit(q);
 }
 
 /**

Reply via email to