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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 758D5C433EF for ; Wed, 15 Jun 2022 13:21:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346806AbiFONVx (ORCPT ); Wed, 15 Jun 2022 09:21:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57418 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231524AbiFONVw (ORCPT ); Wed, 15 Jun 2022 09:21:52 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A43F3B02F; Wed, 15 Jun 2022 06:21:52 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id A075B68AA6; Wed, 15 Jun 2022 15:21:47 +0200 (CEST) Date: Wed, 15 Jun 2022 15:21:47 +0200 From: Christoph Hellwig To: Qu Wenruo Cc: Christoph Hellwig , dsterba@suse.cz, syzbot , akpm@linux-foundation.org, clm@fb.com, dsterba@suse.com, 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: <20220615132147.GA18252@lst.de> References: <0000000000003ce9d105e0db53c8@google.com> <00000000000085068105e112a117@google.com> <20220613193912.GI20633@twin.jikos.cz> <20220614071757.GA1207@lst.de> <2cc67037-cf90-cca2-1655-46b92b43eba8@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2cc67037-cf90-cca2-1655-46b92b43eba8@gmx.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Jun 14, 2022 at 04:50:22PM +0800, Qu Wenruo wrote: > The same way as data? > > map-logical to find the location of a mirror, write 4 bytes of zero into > the location, then call it a day. > > Although for metadata, you may want to choose a metadata that would > definitely get read. > Thus tree root is a good candidate. And how do I find out the logic address of the tree root?