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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25796C43381 for ; Mon, 18 Mar 2019 17:28:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F015F20854 for ; Mon, 18 Mar 2019 17:28:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726767AbfCRR2J (ORCPT ); Mon, 18 Mar 2019 13:28:09 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:38316 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726765AbfCRR2J (ORCPT ); Mon, 18 Mar 2019 13:28:09 -0400 Received: by mail-pf1-f196.google.com with SMTP id n125so11722628pfn.5; Mon, 18 Mar 2019 10:28:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=5KE4wyfuPK8v8HlyIMBIYRZHkOOdHrncsG0EpVpGZwU=; b=C7EXqa+Mw2udDaXmJMom8Bu3DzTWeTpo2I6vv3aYnm8+wlMi1g8gZyZbMAVT7MfPKK QpWZ+mAr1U70q40ropFirP1/CxJnaS8+KPmRBRLYKjZMnGiejuy8Z6ZVS6zGux9Oj5GA 3Gva1m1UCiA5kFIXdMT0wXjuLk/wvwHK1r90uKpj34vF2saUwRLaNSJ3H70fLcJF1/Vn gm10jnwaghpq+2OWmBxJlIuyRYrM9plRK9OBr8aKeX+wpWx/KcpempZq9Vt3N5wKRf/S 94OmZZVqTL4dqfdbLjVtob3V6+8UFyDffEE5agas44Md6vuuaAqQNNXqIoNOPdeqJjf1 ZBlw== X-Gm-Message-State: APjAAAWvZgrmk8TyvTdAsNrtLyMSu3qkC9p1JX5oF+ASg1BRmd87abhJ AmjPbQLV0SlmTVDWj6RaOtE= X-Google-Smtp-Source: APXvYqxgsrVM9i5/x26a7Ori9du9Nh5vFam+SaNl68I4xRJ3CN5fa89ZLkFSxN2qHUjoGCIC6ZaE4Q== X-Received: by 2002:a63:ef57:: with SMTP id c23mr8565915pgk.176.1552930088073; Mon, 18 Mar 2019 10:28:08 -0700 (PDT) Received: from ?IPv6:2620:15c:2cd:203:5cdc:422c:7b28:ebb5? ([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id m32sm1137034pgb.13.2019.03.18.10.28.06 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 18 Mar 2019 10:28:06 -0700 (PDT) Message-ID: <1552930085.152266.36.camel@acm.org> Subject: Re: [PATCH 0/8]: blk-mq: use static_rqs to iterate busy tags From: Bart Van Assche To: Jianchao Wang , axboe@kernel.dk Cc: hch@lst.de, jthumshirn@suse.de, hare@suse.de, josef@toxicpanda.com, sagi@grimberg.me, keith.busch@intel.com, jsmart2021@gmail.com, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Date: Mon, 18 Mar 2019 10:28:05 -0700 In-Reply-To: <1552640264-26101-1-git-send-email-jianchao.w.wang@oracle.com> References: <1552640264-26101-1-git-send-email-jianchao.w.wang@oracle.com> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, 2019-03-15 at 16:57 +-0800, Jianchao Wang wrote: +AD4 +AFs-2+AF0 https://marc.info/?l+AD0-linux-block+ACY-m+AD0-154526189023236+ACY-w+AD0-2 Hi Jianchao, That is a reference to the +ACI-BUG: KASAN: use-after-free in bt+AF8-iter+ACI issue. I think that issue can be fixed in another way than modifying all code that iterates over tags, namely by adding an rcu+AF8-read+AF8-lock() / rcu+AF8-read+AF8-unlock() pair in bt+AF8-for+AF8-each() and bt+AF8-tags+AF8-for+AF8-each() and by changing the calls in blk+AF8-mq+AF8-free+AF8-rqs() and blk+AF8-free+AF8-flush+AF8-queue() that free the data structures used by the tag iteration functions into kfree+AF8-rcu() or call+AF8-rcu() calls. Thanks, Bart.