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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,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 CAB34ECE58C for ; Mon, 7 Oct 2019 19:19:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AB5A21479 for ; Mon, 7 Oct 2019 19:19:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570475964; bh=efUUidLReXlgZH1SzPTDouesSbtgzzkvWDaHCE2GJOg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=J3sFV3vs5z1qfzxLUR0t/ehKtlyzR1Bp1Hok5qhTKUTwVl/eFrBpQ34dZP6so3H85 kb1SrCOPF6dOW461dqMf4K2FwxCQj0GQ+tb1miSceUATHTL3ogIWwta2xnGnouShLn EIk7nD+KbRQx2CRytXseLN4o6iC/7/A0GCBDTw+0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729244AbfJGTTV (ORCPT ); Mon, 7 Oct 2019 15:19:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:42794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728187AbfJGTTV (ORCPT ); Mon, 7 Oct 2019 15:19:21 -0400 Received: from gmail.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9FCE92070B; Mon, 7 Oct 2019 19:19:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570475960; bh=efUUidLReXlgZH1SzPTDouesSbtgzzkvWDaHCE2GJOg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SthwJhFld0F1fA0uA2kRrAX2XVsQ4Y4S2F2Ers2HXtFDNh0L/OKq7AsxSI16RKWYd WKmmm/GxLS0Auzgqn3sNNZuiLDjaTyb9mA5sB9bhah0wmOs6BTDuUr3y0OT4sl38vP s0DjYWr13zz2HaJ2od7wIeAmMJT3bdqZp6QGDh1Q= Date: Mon, 7 Oct 2019 12:19:19 -0700 From: Eric Biggers To: Linus Torvalds Cc: syzbot , linux-fsdevel , Linux Kernel Mailing List , syzkaller-bugs , Al Viro Subject: Re: WARNING in filldir64 Message-ID: <20191007191918.GD16653@gmail.com> Mail-Followup-To: Linus Torvalds , syzbot , linux-fsdevel , Linux Kernel Mailing List , syzkaller-bugs , Al Viro References: <0000000000006b7bfb059452e314@google.com> <20191007190747.GA16653@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Oct 07, 2019 at 12:14:33PM -0700, Linus Torvalds wrote: > On Mon, Oct 7, 2019 at 12:07 PM Eric Biggers wrote: > > > > Seems this indicates a corrupt filesystem rather than a kernel bug, so using > > WARN_ON is not appropriate. It should either use pr_warn_once(), or be silent. > > I was going to silence it for the actual 5.4 release, but I wanted to > see if anybody actually triggers it. > > I didn't really _expect_ it to be triggered, to be honest, so it's > interesting that it did. What is syzbot doing? > > If this is syzbot doing filesystem image randomization, then it falls > under "ok, expected, ignore it, we'll silence it for 5.4" > > But if it's syzbot doing something else, then it would be interesting > to hear what it's up to. > It got there via fat_readdir(), and in the console log there is: syz_mount_image$vfat(&(0x7f0000000540)='vfat\x00', &(0x7f00000002c0)='./file0\x00', 0x800000000e004, 0x1, &(0x7f0000000140)=[{&(0x7f0000010000)="eb3c906d6b66732e666174000204010002000270fff8", 0x16}], 0x0, 0x0) So it seems to have generated a corrupt filesystem image and tried to mount it. - Eric