From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1716434-1523967031-2-1800631597176214677 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='de', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1523967030; b=Z3MIXnoVXl8k7diW1yxm5zM5fE6xJCCn5YfcgPkiT+LLZ7ENX5 RCCAY4ag/XHpEyBatqClGxQKHiIV5/Tu1ZuBZ/SjcyZ8W9ikovXb7VFBp0GortgU /hLnz1/5WWInpz5poAQgeDHGn3Xf8UXfIt/Ck3NxdBETlv5DlxOmm0uIeF9U4m9z cH5ZbYO5xzai4MVSJdq3dpWVUsHDqKgRGGNH5HNt8AQ/NOSNup2P8c9UeuxaTiKD TdmbwvYjulUwPPZ9P2+FgX87d9CjM0RjNK2SIWhctzd2IAfEk7LmnF1SjlO76LzE CRNGdEoeLwjB+vIzj//d8qCoHtHyCIk/FkjA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding :content-type:sender:list-id; s=fm2; t=1523967030; bh=3HbJE2M+7T fKBjRTAKWaj/aD5clas/rTcjJr+wtu1Pc=; b=l3IoAzUcBbHBOU1uWTQ0f47+3Y ofCudD5ezlPIsALApBEoN2AF8TSCrMbgQa78NqSQ1cjO9+x/pJeAUe6YNXn2S97I pHS5z9xZHV2PGw9bhMxV6nBuqBJmP7GAc3Jv3I2z50Yw6JDoBuVrabYWe8e/Kd4M 256kB7Uq919L6VGL9bTq3Mn9yhAW7RWBlaNpzrwMYuCgHcVftZSkDdsoV8EZY0Rl h5Rk0c4p25MJIs+jWYMYWBxkJSWKVGETK62pbH2j//SSD5Jk6ybuQ8FePDCd4Nza 2v0qm25ZfrZnvMD5V4RSpq4xsFw5IpMBEwpPEpQwpk06quLC/k4PSk3UmsIw== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lichtvoll.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lichtvoll.de header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=lichtvoll.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lichtvoll.de header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfBaeo00B4NLI81Zlb2Ducs/5JHS4lnn2ZkTvnOvVzaloN1QH3sxwm/HoXKkrlxs4PpUO9PR2sg7+tFVYBjy9/I1dkCz45emUhXj8MM1Q6c6sufgfGPcz +6UQAQ/MWBXElRCfFt65zhXohp46w/AeZvUVWLl/iq1iqmYh9BbkIfvOQ7gnowDK0QTvW2UmqCAvpgInQVrqMd8OiElMtxkXaIErxhbqi96PsdZNrXKNXPoY X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=kj9zAlcOel0A:10 a=Kd1tUaAdevIA:10 a=JF9118EUAAAA:8 a=VwQbUJbxAAAA:8 a=20KFwNOVAAAA:8 a=yPCof4ZbAAAA:8 a=I9QjSo0uVMMpW2p-shAA:9 a=0Go2i65TiDG78nCO:21 a=B7VonkaQ8JXOjMJ6:21 a=CjuIK1q_8ugA:10 a=xVlTc564ipvMDusKsbsT:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752655AbeDQMKR (ORCPT ); Tue, 17 Apr 2018 08:10:17 -0400 Received: from mondschein.lichtvoll.de ([194.150.191.11]:57487 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752546AbeDQMKQ (ORCPT ); Tue, 17 Apr 2018 08:10:16 -0400 Authentication-Results: auth=pass smtp.auth=martin smtp.mailfrom=martin@lichtvoll.de From: Martin Steigerwald To: Jianchao Wang Cc: axboe@kernel.dk, bart.vanassche@wdc.com, tj@kernel.org, ming.lei@redhat.com, stable@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] blk-mq: start request gstate with gen 1 Date: Tue, 17 Apr 2018 14:10:08 +0200 Message-ID: <2612135.Ur0PZolWSD@merkaba> In-Reply-To: <1523936780-1589-1-git-send-email-jianchao.w.wang@oracle.com> References: <1523936780-1589-1-git-send-email-jianchao.w.wang@oracle.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hi Jianchao, Jianchao Wang - 17.04.18, 05:46: > rq->gstate and rq->aborted_gstate both are zero before rqs are > allocated. If we have a small timeout, when the timer fires, > there could be rqs that are never allocated, and also there could > be rq that has been allocated but not initialized and started. At > the moment, the rq->gstate and rq->aborted_gstate both are 0, thus > the blk_mq_terminate_expired will identify the rq is timed out and > invoke .timeout early. For testing it I add it to 4.16.2 with the patches I have already? - '[PATCH] blk-mq_Directly schedule q->timeout_work when aborting a request.mbox' - '[PATCH v2] block: Change a rcu_read_{lock,unlock}_sched() pair into rcu_read_{lock,unlock}().mbox' - '[PATCH V4 1_2] blk-mq_set RQF_MQ_TIMEOUT_EXPIRED when the rq'\''s timeout isn'\''t handled.mbox' - '[PATCH V4 2_2] blk-mq_fix race between complete and BLK_EH_RESET_TIMER.mbox' > For scsi, this will cause scsi_times_out to be invoked before the > scsi_cmnd is not initialized, scsi_cmnd->device is still NULL at > the moment, then we will get crash. > > Cc: Bart Van Assche > Cc: Tejun Heo > Cc: Ming Lei > Cc: Martin Steigerwald > Cc: stable@vger.kernel.org > Signed-off-by: Jianchao Wang > --- > block/blk-core.c | 4 ++++ > block/blk-mq.c | 7 +++++++ > 2 files changed, 11 insertions(+) > > diff --git a/block/blk-core.c b/block/blk-core.c > index abcb868..ce62681 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -201,6 +201,10 @@ void blk_rq_init(struct request_queue *q, struct > request *rq) rq->part = NULL; > seqcount_init(&rq->gstate_seq); > u64_stats_init(&rq->aborted_gstate_sync); > + /* > + * See comment of blk_mq_init_request > + */ > + WRITE_ONCE(rq->gstate, MQ_RQ_GEN_INC); > } > EXPORT_SYMBOL(blk_rq_init); > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index f5c7dbc..d62030a 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -2069,6 +2069,13 @@ static int blk_mq_init_request(struct > blk_mq_tag_set *set, struct request *rq, > > seqcount_init(&rq->gstate_seq); > u64_stats_init(&rq->aborted_gstate_sync); > + /* > + * start gstate with gen 1 instead of 0, otherwise it will be equal > + * to aborted_gstate, and be identified timed out by > + * blk_mq_terminate_expired. > + */ > + WRITE_ONCE(rq->gstate, MQ_RQ_GEN_INC); > + > return 0; > } -- Martin