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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6306BCD5BB1 for ; Fri, 22 May 2026 13:00:57 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4gMQPh0BcFz3brt; Fri, 22 May 2026 23:00:56 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=172.234.252.31 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1779454855; cv=none; b=gkY0C6P/sCOCagisXOz8zIzn8ZWlZ4N8TYbIlvzxBHxB+quNm9fvflVqcTK/E+yqpSK+byuUEcJJTlrtOAhKXrICcZWkkgFBysw+t385lXcH8Mqkl1v/Xu4Dx6jw+vZ6bp/7QpX+qtjY2WAhIP2pC5Pswv4sp37W6TOFoyt0Jk8SBunTwU1p0iVwHMf1AEawQLfxHktXdPtble3L5yHE2kauVwerCsTzVk2O7/S/st0uB74zIS1VwpHm3+BQGIBicl3Jpvd53qSST1SmiLyvw2r3lKXqWXuKAR9ecmWvf/zKQYvmH99G/TdZXhIlKzwqBibEW1366ResSgpXqgdAzQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1779454855; c=relaxed/relaxed; bh=OdGOR+CUQyFp0PV7PuODPQaFA4X8MLPl0TjPH8ZUT18=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=RniKQPYiXwb94KFjvN43mfw6mpYT/cPWEFvJ9AcE+siHCuUyZBvpB/YU4+XKAM5BK0FQlP0jypbuazhxPzoPxT1NS0ZHOkeRqvW1/r6suC+2zbhaGkdu40N53rMLAdwFZAshpUg2PydIV5BQxNdjRDQEfPWm5wO4f6jE/Sau/O2YQBE8aPOnauH+B1Z7nmEQTYe9zWzoyZZH5MK5fR0NYU8EKjkSBrqloUL6cvpEBZkKynu64jl1FFCPXvc/smh8ydSv1BqbOvMlNgbqhRGERGJh2UpraWln67EWFFMVSffLL8KiiIgXynCqfGSR34yBJqVB1mihP9T//qlH7YS9mw== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ORdRuBAV; dkim-atps=neutral; spf=pass (client-ip=172.234.252.31; helo=sea.source.kernel.org; envelope-from=chao@kernel.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.org Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ORdRuBAV; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=172.234.252.31; helo=sea.source.kernel.org; envelope-from=chao@kernel.org; receiver=lists.ozlabs.org) Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4gMQPb2lYpz2xSN for ; Fri, 22 May 2026 23:00:51 +1000 (AEST) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 5B5744080F; Fri, 22 May 2026 13:00:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78DB01F000E9; Fri, 22 May 2026 13:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779454849; bh=OdGOR+CUQyFp0PV7PuODPQaFA4X8MLPl0TjPH8ZUT18=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=ORdRuBAVydQRpL1PrvM/X5gpv3T0dRzn8dkIcm9HgZ2yuDAduWpEiXA9TRvXfVtq1 sJBjornr9KIB62nKrDLCj3NuILIUkXZ4wWbbMTWw5sgaJRZMNIDNrazeMdzQ+hMj7P HDbaPEd5UpLc2ode4clZ5W+zlRTmMTFr7Hd7mx0G/kPXR4cC8NR5YG2dIfYnvL87S9 GrIrFUuUJ12mmAdobqJA6v2IgKLsF+ysSLDicwC78vABI+AoyowwirI5NTzfn8fmLE Q5SShJnhhgFZQRZI4JSdwCqCLxlSSxr6EhupHFMclkxQVqnDyCf7xx5RBqPutdZg28 7HEfCp3ETk3pw== Message-ID: <4fb20b32-5651-4aff-9a4f-8db5652db476@kernel.org> Date: Fri, 22 May 2026 21:00:44 +0800 X-Mailing-List: linux-erofs@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, LKML , oliver.yang@linux.alibaba.com, syzbot+52bae5c495dbe261a0bc@syzkaller.appspotmail.com Subject: Re: [PATCH] erofs: fix use-after-free on sbi->sync_decompress To: Gao Xiang , linux-erofs@lists.ozlabs.org References: <20260522082716.3598160-1-hsiangkao@linux.alibaba.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260522082716.3598160-1-hsiangkao@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/22/26 16:27, Gao Xiang wrote: > z_erofs_decompress_kickoff() can race with filesystem unmount, causing > a use-after-free on sbi->sync_decompress. > > When I/O completes, z_erofs_endio() calls z_erofs_decompress_kickoff() > to queue z_erofs_decompressqueue_work() asynchronously. Then, after all > folios are unlocked, unmount workflow can proceed and sbi will be freed > before accessing to sbi->sync_decompress. > > Thread (unmount) I/O completion kworker > queue_work > z_erofs_decompressqueue_work > (all folios are unlocked) > cleanup_mnt > .. > erofs_kill_sb > erofs_sb_free > kfree(sbi) > access sbi->sync_decompress // UAF!! > > Fixes: 40452ffca3c1 ("erofs: add sysfs node to control sync decompression strategy") > Reported-by: syzbot+52bae5c495dbe261a0bc@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=52bae5c495dbe261a0bc > Signed-off-by: Gao Xiang Reviewed-by: Chao Yu Thanks,