From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from esa3.hgst.iphmx.com ([216.71.153.141]:33587 "EHLO esa3.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754468AbdD0Pyt (ORCPT ); Thu, 27 Apr 2017 11:54:49 -0400 From: Bart Van Assche To: Jens Axboe CC: , Bart Van Assche , Hannes Reinecke , Omar Sandoval , Ming Lei , Subject: [PATCH 1/6] blk-mq: Make blk_mq_quiesce_queue() wait for all .queue_rq() calls Date: Thu, 27 Apr 2017 08:54:32 -0700 Message-ID: <20170427155437.23228-2-bart.vanassche@sandisk.com> In-Reply-To: <20170427155437.23228-1-bart.vanassche@sandisk.com> References: <20170427155437.23228-1-bart.vanassche@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain Sender: stable-owner@vger.kernel.org List-ID: 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 Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei Cc: --- 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