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 865A4C4332F for ; Tue, 14 Nov 2023 15:05:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233426AbjKNPFw (ORCPT ); Tue, 14 Nov 2023 10:05:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbjKNPFv (ORCPT ); Tue, 14 Nov 2023 10:05:51 -0500 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3503126 for ; Tue, 14 Nov 2023 07:05:23 -0800 (PST) Received: by mail-pl1-x62e.google.com with SMTP id d9443c01a7336-1cc2f17ab26so42178025ad.0 for ; Tue, 14 Nov 2023 07:05:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1699974323; x=1700579123; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=YG9lz3Q7V8byQ3pbms3zFQZsFgW+qQ2vsca18euKUKo=; b=KC7r38fjLbxCsGe8xaM+fFxwMiOR7rXQFPO2eKOAHia9fRMYLw4/4ZxLW59pjD1IgD KMmmkMipfBoJqj/HQDqZO5mxtgPqLRA/+saQslTsaoBqeQ55yWIqhQRmAp09aFWgdKCQ AHHlTMMJyWZD0nbZr3z84GdM/e5lWb1mapcz931dMeteNa9VxAGb65/foAnykKyZO/+6 q0IZSEol2qN2cPNvZC6DFpbB2RyTZjKQq+wKRqXslCl6cUPLnw7jkSKn9M4+63hjbX4B KfZmk9z2sEEu84NUUEbbtZNslrvM7/SNVvEtVaMil2dNKD6WiuT1S2GiSDYr7/nE0ECM aLsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699974323; x=1700579123; h=content-transfer-encoding:in-reply-to:from:references:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=YG9lz3Q7V8byQ3pbms3zFQZsFgW+qQ2vsca18euKUKo=; b=DmmVBnMSdbR5jcjdgUzVqu7qRuwCZk9sIlPlmEh3Aq4xQ1bOoVZay2/POgMNt4/3UM MbrsGBNtSp18G1Y7wIiN1/1g+WrB4veavhIHctX7ywrYA6EeWUVrWdgIpgiwbEavmCXP mKUD73sJhdoTpgcqYMz5WrLD/7gCs+Xvf0AU52hi8EsdTNSBWh5rHQ2O/uKEXhUocWxl IlWh+wZ0SzKfM7uVEGg8OLifXRIZt0eS/6tXjYYAnmOaL2giSqUaV51/jZoPdM4FLlds JQ6QKgaRfT24fhRwFIbTXBSqRlJgxtysxz9AAfkfegA07YzJNXYwsk5xFl1Uvx9BP/mU Ex4A== X-Gm-Message-State: AOJu0YzHa42o5lIwPHdd4TeRS7xHi9GatAGedmt9OxKI8sTVWbX3DLCU OMrUTjEWrmFx8srpvQXQxrYIAg== X-Google-Smtp-Source: AGHT+IEnIN5gyz/hEms93r0CqoIg3S5ZdYQSCrRMRRSvX1FVrXZLdluDJR3bBHguvUPLHjv3/6pbjQ== X-Received: by 2002:a17:902:a401:b0:1cc:5899:112c with SMTP id p1-20020a170902a40100b001cc5899112cmr2290346plq.23.1699974323110; Tue, 14 Nov 2023 07:05:23 -0800 (PST) Received: from ?IPV6:2409:8a28:e60:6e40:5de2:6afc:2f43:5fdc? ([2409:8a28:e60:6e40:5de2:6afc:2f43:5fdc]) by smtp.gmail.com with ESMTPSA id k7-20020a170902c40700b001bc2831e1a8sm5788558plk.80.2023.11.14.07.05.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Nov 2023 07:05:22 -0800 (PST) Message-ID: <7fdb796f-9301-4898-b038-cc4f546192e2@bytedance.com> Date: Tue, 14 Nov 2023 23:05:15 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [External] Re: [syzbot] [block?] WARNING in blk_mq_start_request Content-Language: en-US To: Bart Van Assche , syzbot , axboe@kernel.dk, chaitanyak@nvidia.com, eadavis@qq.com, hch@infradead.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ming.lei@redhat.com, syzkaller-bugs@googlegroups.com References: <00000000000077ca930609aa9f86@google.com> <7ed9f6f9-d309-4d30-9b3b-c465cfa48a52@bytedance.com> <3f2c2d33-2e5d-4c7b-80ea-e76885981dfb@acm.org> From: Chengming Zhou In-Reply-To: <3f2c2d33-2e5d-4c7b-80ea-e76885981dfb@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/11/14 07:57, Bart Van Assche wrote: > On 11/13/23 07:05, Chengming Zhou wrote: >> Ok, I reviewed the code of virtio_queue_rqs(), found the main difference >> is that request won't fail after blk_mq_start_request(). >> >> But in null_blk case, the request will fail after blk_mq_start_request(), >> return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE. If we return these rqs >> back to the block layer core, they will be queued individually once again. >> So caused the warning. > > I think it is safe to move the blk_mq_start_request() call under the if-block > that decides whether or not to requeue a request in null_queue_rq() > Right! And null_handle_throttled() in null_handle_cmd() may also return the BLK_STS_DEV_RESOURCE, it's also needed to put in null_queue_rq() and before the blk_mq_start_request(). Then request must return BLK_STS_OK after blk_mq_start_request(). Thanks!