From nobody Sun Feb 8 13:10:52 2026 Received: from mail-m3298.qiye.163.com (mail-m3298.qiye.163.com [220.197.32.98]) (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 5590C262808 for ; Sat, 20 Dec 2025 12:09:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.32.98 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766232576; cv=none; b=cBpvf8vfmcAhEoJxR4hxiOY7gl2b/pD6GCUDNSaqb+oktMqYzY841yh355Yzj4K60Vo4ca8YjmfhlemoOJdzPSiBFBbWIXEdakyzRy6Rn4FwFuQM3VICL2RF10Cyd0H8CIgbQS4P7nGEK/jWJLPP8E4zmZVEpa6ezCKxpky+sAc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766232576; c=relaxed/simple; bh=wa97D9YrxtxrOKaLK2XxwTEFhYlqQUdHTvlzwKwoiik=; h=From:To:Cc:Subject:Date:Message-Id; b=tNSVk7TOzjoPZGru82XMka1BWrUxlkeLLFeDCvqyDkkCvIW4shvi5t/EEvX+bZB0JcDrctnioUDWyqArsfoplh3hO/SqL5YBXjbDrEDSzz72O/p0SScHc3anq63RtRc+kWyj2Lad9c7qHluFqqCRW3MXSoQE8JCKxsdKNCVlfq4= 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=220.197.32.98 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 localhost.localdomain (unknown [113.92.156.73]) by smtp.qiye.163.com (Hmail) with ESMTP id 2df8d417d; Sat, 20 Dec 2025 20:04:14 +0800 (GMT+08:00) From: Ding Hui To: linux-kernel@vger.kernel.org, dm-devel@lists.linux.dev Cc: bmarzins@redhat.com, mpatocka@redhat.com, snitzer@kernel.org, agk@redhat.com, hch@lst.de, Ding Hui Subject: [PATCH] dm: remove fake timeout to avoid leak request Date: Sat, 20 Dec 2025 20:03:50 +0800 Message-Id: <20251220120350.10750-1-dinghui@sangfor.com.cn> X-Mailer: git-send-email 2.17.1 X-HM-Tid: 0a9b3ba568b209d9kunm015e7bae884f60 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVkZT04eVktNThhLGRlNGkpLGlYVFAkWGhdVEwETFh oSFyQUDg9ZV1kYEgtZQVlKSkhVQklVSk5NVUxIWVdZFhoPEhUdFFlBWU9LSFVKS0lPT09IVUpLS1 VKQktLWQY+ Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 seco= nds. [ 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_trans= port_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 Reviewed-by: Christoph Hellwig --- 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 =3D tio_from_request(rq); =20 tio->error =3D error; - if (likely(!blk_should_fake_timeout(rq->q))) - blk_mq_complete_request(rq); + blk_mq_complete_request(rq); } =20 /* --=20 2.17.1