From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 058D837BE85 for ; Mon, 12 Jan 2026 17:27:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768238881; cv=none; b=FyAXzK8vWIrRlz2JG0UuODKhXpTupu86cJgUqkQh7IMKrOujn5ZcyvO8d8j0ebi5nLwj5P84cc3pbp3Tsi2MsJC5qFgb2kbaYihZl4/dqgLZHDSN3Ez3RaJFDzIUWB3LlEJAoBtMfgryR/hHq7h6aqYWxizqtlyWr7eGrx2Kogk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768238881; c=relaxed/simple; bh=rhZp3FhpkdvJFqfyP0R3sWiIkQM5geDMCm3gNb14hxo=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=rCCuxrC7jXJG+TnDyH0uCPuCZHcWzckNXs7eX4GOT3TsjuI4/KF6si1HpIPJMDSEtX4YbQStuwq+PeSKlHVYhjraxERn3Dg+9c6jdebqL8D8vxt28Zwgxdgwx2Z6m8hHUQDYsgSAXjqY6xP3Msz+2KM9h1hQ41dsim3XkuoAQug= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=iDlglwEk; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iDlglwEk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768238879; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=UYlFYflaiicRhHjlBUOwOc9xyibnzsVwIEkt7Cu3ORY=; b=iDlglwEkfEVnZo3vwqhD5Yw2dMPZQwBoxy33nbvKXsCqh7AS5z90aE+Hoqf27gLnXSjrUw VH5PrGujm022hpSCRSCQOYYVqOb2RkBUM3BJRK6p+tKPDTSTrsNPAPomPMHVn6wOwtxml3 E3KvarbGdl2Bhl7bsdqdKNQ6ClXjmz0= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-387-UMTWbY2IMdG5Or4frSzUwg-1; Mon, 12 Jan 2026 12:27:54 -0500 X-MC-Unique: UMTWbY2IMdG5Or4frSzUwg-1 X-Mimecast-MFC-AGG-ID: UMTWbY2IMdG5Or4frSzUwg_1768238873 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0124718002CF; Mon, 12 Jan 2026 17:27:53 +0000 (UTC) Received: from [10.44.33.27] (unknown [10.44.33.27]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D29EF30001A2; Mon, 12 Jan 2026 17:27:50 +0000 (UTC) Date: Mon, 12 Jan 2026 18:27:45 +0100 (CET) From: Mikulas Patocka To: Ding Hui cc: agk@redhat.com, snitzer@kernel.org, bmarzins@redhat.com, hch@lst.de, dm-devel@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dm: remove fake timeout to avoid leak request In-Reply-To: <61d6db2d-30f8-4c20-8fca-60a0cb9f3baa@sangfor.com.cn> Message-ID: References: <20251220120350.10750-1-dinghui@sangfor.com.cn> <61d6db2d-30f8-4c20-8fca-60a0cb9f3baa@sangfor.com.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Mon, 12 Jan 2026, Ding Hui wrote: > 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. Hi I committed the patch - it is in the linux-dm git, branch for-next. Mikulas > 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 >