From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp153-141.sina.com.cn (smtp153-141.sina.com.cn [61.135.153.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC2D031F9AC for ; Thu, 28 May 2026 05:43:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=61.135.153.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779947043; cv=none; b=OLHfUIH8Zo8JJFI6CY0e0zkKjmQ7q/BUZOtwUoY/MCVkGYB+9o7ybWmDb6e0kle7hf/74u5wl0ku+8oca4eBbDtXLWQn9ngA0SWPFTQFX7a0LEX/QDJ/rKB4Ypg1C4pN8iUAtKDmwTvYv1Rx6y4oZydTbAY9XnT2SwDmxPnxe9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779947043; c=relaxed/simple; bh=C7JHlHzPIIDbcrjvTTaZykxa0kwfZ19sATnFMjQgAWY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kN/rCjxzaFitJ3i0NST+PrUYDT2juWWNztbpgw4+9NisOEyilqWWMHoUMbL0keN9gQ7u+du58c5+5whBAAtejcEdxhSu8s4CnAee7BXOHsxyDyQ6F7A5Rh2uP0+BRdF+mC1Ti5nkDqZqcY/H17HGEBFxylozjGh4vSO7dnjlmI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=YyHuquYr; arc=none smtp.client-ip=61.135.153.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="YyHuquYr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1779947038; bh=cx/MeDnSm8Ccc4831CYFK65RBNwl+E+0XHr2pEV7eW0=; h=From:Subject:Date:Message-ID; b=YyHuquYrKfqpe5s8iHt7iBV7t5ls6Ae8gnTskxDpQ1qs8Gb6Hjol7MPEhNvhAU1S5 7Jj2ZYunKvMIfZ8tE/eTLsW/QPW1HtX9KuzJXNVAeTTSdt9lLFS+6kAuibQ+UlSEWh ObFOCU2reHfW+OXkdyLOE4FLuIUyax/JpsElPMPs= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.62.144]) by sina.com (10.54.253.31) with ESMTP id 6A17D60E000062C1; Thu, 28 May 2026 13:43:45 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 9341726816115 X-SMAIL-UIID: 4C03AE2645D34C15B349F3C5E267BA13-20260528-134345-1 From: Hillf Danton To: Ming Lei Cc: Tetsuo Handa , Jens Axboe , Bart Van Assche , Christoph Hellwig , Damien Le Moal , linux-block , LKML , Andrew Morton , Linus Torvalds , linux-btrfs@vger.kernel.org, David Sterba , linux-fsdevel@vger.kernel.org, Christian Brauner Subject: Re: [PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() Date: Thu, 28 May 2026 13:43:31 +0800 Message-ID: <20260528054334.1159-1-hdanton@sina.com> In-Reply-To: References: <94076bc9-2c09-4bb6-8468-b6b8af419cb9@I-love.SAKURA.ne.jp> <1ab8c579-eb76-4227-8a72-6ec819135219@I-love.SAKURA.ne.jp> <1a9f53d4-6f48-4df8-a3d8-2b0e442a163a@I-love.SAKURA.ne.jp> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Tue, 26 May 2026 22:00:49 -0500 Ming Lei wrote: >On Wed, May 27, 2026 at 10:35:56AM +0900, Tetsuo Handa wrote: >> On 2026/05/27 10:20, Ming Lei wrote: >> >> Of course we should try to figure out the root cause first, but how can we do? >> > >> > Definitely unexpected write IO(after umount & loop closed) from btrfs is more serious, >> > which may cause data loss, so CC btrfs list and maintainer. >> >> Why do you assume that the culprit is btrfs? >> >> https://syzkaller.appspot.com/bug?extid=bc273027d5643e48e5b3 indicated that >> this similar race is also happening with jfs. > > I just didn't see the above report on jfs. > > It doesn't change anything, the same question still stands: unexpected write IO is issued > or crosses umount & last closing of loop disk. > Given the loop workqueue that triggered the jfs warning, can you specify the reason why the workqueue in question is NOT flushed while closing disk?