From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EF3EC77B7A for ; Thu, 25 May 2023 08:14:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239027AbjEYIO4 (ORCPT ); Thu, 25 May 2023 04:14:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239544AbjEYIOx (ORCPT ); Thu, 25 May 2023 04:14:53 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA2F2186 for ; Thu, 25 May 2023 01:14:41 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 1CEA868B05; Thu, 25 May 2023 10:14:38 +0200 (CEST) Date: Thu, 25 May 2023 10:14:37 +0200 From: Christoph Hellwig To: Bart Van Assche Cc: Christoph Hellwig , Jens Axboe , Damien Le Moal , linux-block@vger.kernel.org Subject: Re: [PATCH 4/7] blk-mq: use the I/O scheduler for writes from the flush state machine Message-ID: <20230525081437.GA22420@lst.de> References: <20230519044050.107790-1-hch@lst.de> <20230519044050.107790-5-hch@lst.de> <20230524055327.GA19543@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, May 24, 2023 at 11:07:41AM -0700, Bart Van Assche wrote: > On 5/23/23 22:53, Christoph Hellwig wrote: >> I turns out this causes some kind of hang I haven't been able to >> debug yet in blktests' hotplug test. Can you drop this and the >> subsequent patches for now? > > Hi Christoph, > > I haven't seen this hang in my tests. If you can tell me how to run > blktests I can help with root-causing this issue. This is how I run > blktests: This is a simple ./check run with this config, and most importantly modular scsi_debug (which is not my usual config, othewise I would have noticed it earlier): ----- snip ----- TEST_DEVS=(/dev/vdb) nvme_trtype=tcp ----- snip ----- It hangs in block/001 when probing scsi_debug: [ 242.790601] INFO: task modprobe:3702 blocked for more than 120 seconds. [ 242.791572] Not tainted 6.4.0-rc2+ #1179 [ 242.792201] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 242.793387] task:modprobe state:D stack:0 pid:3702 ppid:3686 flags:0x00004002 [ 242.794724] Call Trace: [ 242.795121] [ 242.795465] __schedule+0x307/0x840 [ 242.796053] ? call_usermodehelper_exec+0xee/0x180 [ 242.796812] schedule+0x57/0xa0 [ 242.797316] async_synchronize_full+0xa0/0x130 [ 242.798029] ? destroy_sched_domains_rcu+0x20/0x20 [ 242.798803] do_init_module+0x19f/0x200 [ 242.799657] __do_sys_finit_module+0x9e/0xf0 [ 242.800324] do_syscall_64+0x34/0x80 [ 242.800879] entry_SYSCALL_64_after_hwframe+0x63/0xcd