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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 386E3C43334 for ; Tue, 14 Jun 2022 07:18:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A8CFF8D0222; Tue, 14 Jun 2022 03:18:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A3E418D0216; Tue, 14 Jun 2022 03:18:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E0378D0222; Tue, 14 Jun 2022 03:18:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 76D4A8D0216 for ; Tue, 14 Jun 2022 03:18:03 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 4EFA960BE8 for ; Tue, 14 Jun 2022 07:18:03 +0000 (UTC) X-FDA: 79575987246.12.9AEEEFF Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf07.hostedemail.com (Postfix) with ESMTP id A05364007E for ; Tue, 14 Jun 2022 07:18:02 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 3BCCF68AA6; Tue, 14 Jun 2022 09:17:58 +0200 (CEST) Date: Tue, 14 Jun 2022 09:17:57 +0200 From: Christoph Hellwig To: dsterba@suse.cz, syzbot , akpm@linux-foundation.org, clm@fb.com, dsterba@suse.com, hch@lst.de, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, willy@infradead.org Subject: Re: [syzbot] KASAN: use-after-free Read in copy_page_from_iter_atomic (2) Message-ID: <20220614071757.GA1207@lst.de> References: <0000000000003ce9d105e0db53c8@google.com> <00000000000085068105e112a117@google.com> <20220613193912.GI20633@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220613193912.GI20633@twin.jikos.cz> User-Agent: Mutt/1.5.17 (2007-11-01) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655191083; a=rsa-sha256; cv=none; b=XeRVMAbCsbBibdtTFSaot3M/+ppcEzru2Cw6gOTo/++25biO+MfJ3xuycklZe+jRmjhBtN jkqr3VSvqVn85KOMB6dm2CFdAz+iatXJocsBpb4PUfzMSXReGD6XAOXpMh58UiDUe4LNw2 zMXm+ewZ1DmCjFor7/8MBnz53tP8f/c= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=none; spf=none (imf07.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655191083; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=h88NdAbI1DP0/kE6eEd1caDjfzw+hBfjognh0PEioxg=; b=zk98Xm7iEF7O0OTjbK9+BtQYbfubU9gm5UnfLQQ5JK/ICwGOO1OHL6vtCtY4G+XnuwTu3a TA5bVE4AaPy/XNf7Obt3pvxkHpCNRCzJXaOzIS4IDjXonETeHXFtusZvG0/qB1ZOEEvzQY JqhQ2kzLJBMGLu53uavd935cdW68hog= Authentication-Results: imf07.hostedemail.com; dkim=none; spf=none (imf07.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none X-Rspam-User: X-Stat-Signature: s3zpni4xnfxonmdq1egtdz4hzcs75kde X-Rspamd-Queue-Id: A05364007E X-Rspamd-Server: rspam08 X-HE-Tag: 1655191082-167233 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jun 13, 2022 at 09:39:12PM +0200, David Sterba wrote: > On Fri, Jun 10, 2022 at 12:10:19AM -0700, syzbot wrote: > > syzbot has bisected this issue to: > > > > commit 4cd4aed63125ccd4efc35162627827491c2a7be7 > > Author: Christoph Hellwig > > Date: Fri May 27 08:43:20 2022 +0000 > > > > btrfs: fold repair_io_failure into btrfs_repair_eb_io_failure > > Josef also reported a crash and found a bug in the patch, now added as > fixup that'll be in for-next: The patch looks correct to me. Two things to note here: - I hadn't realized you had queued up the series. I've actually started to merge some of my bio work with the bio split at submission time work from Qu and after a few iterations I think I would do the repair code a bit differently based on that. Can you just drop the series for now? - I find it interesting that syzbot hits btrfs metadata repair. xfstests seems to have no coverage and I could not come up with a good idea how to properly test it. Does anyone have a good idea on how to intentially corrupt metadata in a deterministic way?