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Tue, 26 May 2026 20:00:57 -0700 (PDT) Date: Tue, 26 May 2026 22:00:49 -0500 From: Ming Lei To: Tetsuo Handa Cc: 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() Message-ID: 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-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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. Thanks, Ming