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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 44BA9C433E0 for ; Fri, 26 Jun 2020 16:47:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE9D520781 for ; Fri, 26 Jun 2020 16:47:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="CQ7eCI8V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727861AbgFZQr2 (ORCPT ); Fri, 26 Jun 2020 12:47:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727847AbgFZQr2 (ORCPT ); Fri, 26 Jun 2020 12:47:28 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 151E1C03E979; Fri, 26 Jun 2020 09:47:28 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 52F92879E; Fri, 26 Jun 2020 12:47:27 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 52F92879E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1593190047; bh=aPpev6+jbpMjykTXQYkoFzkRvxyLE0DzAEOYxd8rSiU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CQ7eCI8VvZx5C558KfIaB1SEBm2kT5+g8WAks5U1BkF+e8Ug1ZPeK0J0/UAGpVtvB +1k/uOO7Qz8/iuJZyz7BZZHHq3e1G4xlhf+9ch3aNUeYLzj/Ky3iev+kj3yaQtlbR2 DiOGzvPQ9EWdDEhat+BWw5GAmOJbTJPHEaFn/PwY= Date: Fri, 26 Jun 2020 12:47:27 -0400 From: "J. Bruce Fields" To: Dmitry Vyukov Cc: Hillf Danton , syzbot , chuck.lever@oracle.com, LKML , linux-nfs@vger.kernel.org, syzkaller-bugs Subject: Re: BUG: unable to handle kernel paging request in rb_erase Message-ID: <20200626164727.GB3565@fieldses.org> References: <0000000000005016dd05a5e6b308@google.com> <20200603043435.13820-1-hdanton@sina.com> <20200603144326.GA2035@fieldses.org> <20200604035359.2516-1-hdanton@sina.com> <20200604215812.GC3458@fieldses.org> <20200625210229.GE6605@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Fri, Jun 26, 2020 at 12:32:42PM +0200, Dmitry Vyukov wrote: > So far this crash happened only once: > https://syzkaller.appspot.com/bug?extid=0e37e9d19bded16b8ab9 > > For continuous fuzzing on syzbot it usually means either (1) it's a > super narrow race or (2) it's a previous unnoticed memory corruption. > > Simpler bugs usually have much higher hit counts: > https://syzkaller.appspot.com/upstream > https://syzkaller.appspot.com/upstream/fixed > > If you did a reasonable looking for any obvious bugs in the code that > would lead to such failure, it can make sense to postpone any > additional actions until we have more info. > If no info comes, at some point syzbot will auto-obsolete it, and then > then we can assume it was (2). OK, thanks. It's a big heavily used data structure, if there was random memory corruption then I guess this wouldn't be a surprising way for it to show up. --b.