From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-m32100.qiye.163.com (mail-m32100.qiye.163.com [220.197.32.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4386F13D53C for ; Mon, 12 Jan 2026 06:43:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.32.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768200218; cv=none; b=Gy1ZKwuFKIGjFCtTcB1Uh1AzAuUtq582FWVz8Sxx1lMKThcehJivLgbQ3biMoXS2ug/Gx1cYluEizX3PuymHD0B+OC+JK8TTz0f2pksNldLUhg2a4IGM3oMmSYHeMmzsaK6E0tXavNw4knflukO6Jkxao9d1MrF+PsyUhkkmj2c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768200218; c=relaxed/simple; bh=27+sKsEFXvCe+Id9t4TnWBzUxp3pZBXOz7op1wBVgaE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cyks3TWYG54qQQnrSuNNjGCu8/26YGHRiR1YrwMX/JBCfipmxbU2UF4zlqWq57wQpt0mve3xQnRpBz/X4kbuabHHOBXJII4gd2dmV+jRS1YYWA2LGlULnyLQmIS9m/1fHRJ8/M3t17N/KxmBt7n8alCaX1iR4g49nQv2AzzCwAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sangfor.com.cn; spf=pass smtp.mailfrom=sangfor.com.cn; arc=none smtp.client-ip=220.197.32.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sangfor.com.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sangfor.com.cn Received: from [172.23.68.66] (unknown [43.247.70.80]) by smtp.qiye.163.com (Hmail) with ESMTP id 304a48559; Mon, 12 Jan 2026 14:43:25 +0800 (GMT+08:00) Message-ID: <61d6db2d-30f8-4c20-8fca-60a0cb9f3baa@sangfor.com.cn> Date: Mon, 12 Jan 2026 14:43:24 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] dm: remove fake timeout to avoid leak request To: agk@redhat.com, snitzer@kernel.org, mpatocka@redhat.com, bmarzins@redhat.com Cc: hch@lst.de, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org References: <20251220120350.10750-1-dinghui@sangfor.com.cn> Content-Language: en-US From: Ding Hui In-Reply-To: <20251220120350.10750-1-dinghui@sangfor.com.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-HM-Tid: 0a9bb0f1f35f09d9kunm2e80ed602b0334 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlCGBhJVkNKT04YHU4aQhlMTlYVFAkWGhdVEwETFh oSFyQUDg9ZV1kYEgtZQVlPSFVJT0xVTEtVQ0tZV1kWGg8SFR0UWUFZT0tIVUpLSU9PT0hVSktLVU pCS0tZBg++ Hi, Sorry for this ping mail as there is no feedback from maintainers, just in case the patch was forgotten somewhere. And it has already received a Reviewed-by from Christoph last month. On 2025/12/20 20:03, Ding Hui wrote: > Since commit 15f73f5b3e59 ("blk-mq: move failure injection out of > blk_mq_complete_request"), drivers are responsible for calling > blk_should_fake_timeout() at appropriate code paths and opportunities. > > However, the dm driver does not implement its own timeout handler and > relies on the timeout handling of its slave devices. > > If an io-timeout-fail error is injected to a dm device, the request > will be leaked and never completed, causing tasks to hang indefinitely. > > Reproduce: > 1. prepare dm which has iscsi slave device > 2. inject io-timeout-fail to dm > echo 1 >/sys/class/block/dm-0/io-timeout-fail > echo 100 >/sys/kernel/debug/fail_io_timeout/probability > echo 10 >/sys/kernel/debug/fail_io_timeout/times > 3. read/write dm > 4. iscsiadm -m node -u > > Result: hang task like below > [ 862.243768] INFO: task kworker/u514:2:151 blocked for more than 122 seconds. > [ 862.244133] Tainted: G E 6.19.0-rc1+ #51 > [ 862.244337] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 862.244718] task:kworker/u514:2 state:D stack:0 pid:151 tgid:151 ppid:2 task_flags:0x4288060 flags:0x00080000 > [ 862.245024] Workqueue: iscsi_ctrl_3:1 __iscsi_unbind_session [scsi_transport_iscsi] > [ 862.245264] Call Trace: > [ 862.245587] > [ 862.245814] __schedule+0x810/0x15c0 > [ 862.246557] schedule+0x69/0x180 > [ 862.246760] blk_mq_freeze_queue_wait+0xde/0x120 > [ 862.247688] elevator_change+0x16d/0x460 > [ 862.247893] elevator_set_none+0x87/0xf0 > [ 862.248798] blk_unregister_queue+0x12e/0x2a0 > [ 862.248995] __del_gendisk+0x231/0x7e0 > [ 862.250143] del_gendisk+0x12f/0x1d0 > [ 862.250339] sd_remove+0x85/0x130 [sd_mod] > [ 862.250650] device_release_driver_internal+0x36d/0x530 > [ 862.250849] bus_remove_device+0x1dd/0x3f0 > [ 862.251042] device_del+0x38a/0x930 > [ 862.252095] __scsi_remove_device+0x293/0x360 > [ 862.252291] scsi_remove_target+0x486/0x760 > [ 862.252654] __iscsi_unbind_session+0x18a/0x3e0 [scsi_transport_iscsi] > [ 862.252886] process_one_work+0x633/0xe50 > [ 862.253101] worker_thread+0x6df/0xf10 > [ 862.253647] kthread+0x36d/0x720 > [ 862.254533] ret_from_fork+0x2a6/0x470 > [ 862.255852] ret_from_fork_asm+0x1a/0x30 > [ 862.256037] > > Remove the blk_should_fake_timeout() check from dm, as dm has no > native timeout handling and should not attempt to fake timeouts. > > Signed-off-by: Ding Hui > --- > drivers/md/dm-rq.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c > index a6ca92049c10..5e0854669614 100644 > --- a/drivers/md/dm-rq.c > +++ b/drivers/md/dm-rq.c > @@ -278,8 +278,7 @@ static void dm_complete_request(struct request *rq, blk_status_t error) > struct dm_rq_target_io *tio = tio_from_request(rq); > > tio->error = error; > - if (likely(!blk_should_fake_timeout(rq->q))) > - blk_mq_complete_request(rq); > + blk_mq_complete_request(rq); > } > > /* -- Thanks, - Ding Hui