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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71D76C433EF for ; Fri, 5 Nov 2021 01:34:42 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3BEE261059 for ; Fri, 5 Nov 2021 01:34:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3BEE261059 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:To: Subject:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; 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Fri, 5 Nov 2021 09:34:18 +0800 Received: from [10.169.46.19] (10.169.46.19) by kwepemm600011.china.huawei.com (7.193.23.229) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.15; Fri, 5 Nov 2021 09:34:18 +0800 Subject: Re: [PATCH 1/1] nvme: fix use after free when disconnect a reconnecting ctrl To: Sagi Grimberg , References: <20211104071332.28952-1-liruozhu@huawei.com> <20211104071332.28952-2-liruozhu@huawei.com> <8165ac91-3ed1-f0c4-16d3-7e6741a610fb@grimberg.me> From: liruozhu Message-ID: <88268d9e-92bf-83ee-13bd-8de2d975e669@huawei.com> Date: Fri, 5 Nov 2021 09:34:17 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.0.1 MIME-Version: 1.0 In-Reply-To: <8165ac91-3ed1-f0c4-16d3-7e6741a610fb@grimberg.me> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [10.169.46.19] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600011.china.huawei.com (7.193.23.229) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211104_183428_700459_514BF9FC X-CRM114-Status: GOOD ( 19.14 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 2021/11/4 20:26, Sagi Grimberg wrote: > >> A crash happens when I try to disconnect a reconnecting ctrl: >> >> 1) The network was cut off when the connection was just established, >> scan work hang there waiting for some IOs complete.Those IOs were >> retrying because we return BLK_STS_RESOURCE to blk in reconnecting. >> >> 2) After a while, I tried to disconnect this connection.This procedure >> also hung because it tried to obtain ctrl->scan_lock.It should be noted >> that now we have switched the controller state to NVME_CTRL_DELETING. >> >> 3) In nvme_check_ready(), we always return true when ctrl->state is >> NVME_CTRL_DELETING, so those retrying IOs were issued to the bottom >> device which was already freed. >> >> To fix this, when ctrl->state is NVME_CTRL_DELETING, issue cmd to bottom >> device only when queue state is live.If not, return host path error >> to blk. >> >> Signed-off-by: Ruozhu Li >> --- >>   drivers/nvme/host/core.c | 1 + >>   drivers/nvme/host/nvme.h | 2 +- >>   2 files changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c >> index 838b5e2058be..752203ad7639 100644 >> --- a/drivers/nvme/host/core.c >> +++ b/drivers/nvme/host/core.c >> @@ -666,6 +666,7 @@ blk_status_t nvme_fail_nonready_command(struct >> nvme_ctrl *ctrl, >>           struct request *rq) >>   { >>       if (ctrl->state != NVME_CTRL_DELETING_NOIO && >> +        ctrl->state != NVME_CTRL_DELETING && > > Please explain why you need this change? As suggested by the name > only DELETING_NOIO does not accept I/O, and if we return > BLK_STS_RESOURCE we can get into an endless loop of resubmission. I just added the handling of the DELETING state here, did not modify the DELETING_NOIO case. Thanks, Ruozhu > >>           ctrl->state != NVME_CTRL_DEAD && >>           !test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags) && >>           !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH)) >> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h >> index b334af8aa264..9b095ee01364 100644 >> --- a/drivers/nvme/host/nvme.h >> +++ b/drivers/nvme/host/nvme.h >> @@ -709,7 +709,7 @@ static inline bool nvme_check_ready(struct >> nvme_ctrl *ctrl, struct request *rq, >>           return true; >>       if (ctrl->ops->flags & NVME_F_FABRICS && >>           ctrl->state == NVME_CTRL_DELETING) >> -        return true; >> +        return queue_live; > > I agree with this change. I thought I've already seen this change from > James in the past. > .