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 X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62F51C433E0 for ; Sun, 26 Jul 2020 15:24:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 431892065E for ; Sun, 26 Jul 2020 15:24:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="P9RXW33o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726065AbgGZPYQ (ORCPT ); Sun, 26 Jul 2020 11:24:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725949AbgGZPYQ (ORCPT ); Sun, 26 Jul 2020 11:24:16 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3DDEC0619D2; Sun, 26 Jul 2020 08:24:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5Z5eIAaFGWLcRkprXsSQSz/ZXR6YtVszbfA9Sx2DBkI=; b=P9RXW33o4c7/2dMj2/ZrliJYVH e7c+NkQFOX6OIGXB8xTc7v5uOpS7Z40n2xtlBe0tqIkRw9nb4vGKxMTMe8aWSLu2KoXQvIl7TS+YB NgkYZ30Man3k/hfFOIripyBF69nyLjO9OzSgH/SkZhYqUgTJYlap/xidu41OQtQiI67pODAcgbI/F /Iw0QcuXPvPhi20xhTTC5OVZdPHIvQrzxY+kb/Ij+XXiOzSg9Tri2S+NifrSesHe6s+lDJfepzWHj KGIEhGzmV3mWfDQQZovPzugaiASv24o/MepucA5rCbhMREvkBmeYge89777+wz+G9Owz4isUC564D y3b2DL1Q==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jziVY-0006x0-Rb; Sun, 26 Jul 2020 15:24:12 +0000 Date: Sun, 26 Jul 2020 16:24:12 +0100 From: Christoph Hellwig To: Qian Cai Cc: Matthew Wilcox , darrick.wong@oracle.com, hch@infradead.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, khlebnikov@yandex-team.ru Subject: Re: WARN_ON_ONCE(1) in iomap_dio_actor() Message-ID: <20200726152412.GA26614@infradead.org> References: <20200619211750.GA1027@lca.pw> <20200620001747.GC8681@bombadil.infradead.org> <20200724182431.GA4871@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200724182431.GA4871@lca.pw> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Jul 24, 2020 at 02:24:32PM -0400, Qian Cai wrote: > On Fri, Jun 19, 2020 at 05:17:47PM -0700, Matthew Wilcox wrote: > > On Fri, Jun 19, 2020 at 05:17:50PM -0400, Qian Cai wrote: > > > Running a syscall fuzzer by a normal user could trigger this, > > > > > > [55649.329999][T515839] WARNING: CPU: 6 PID: 515839 at fs/iomap/direct-io.c:391 iomap_dio_actor+0x29c/0x420 > > ... > > > 371 static loff_t > > > 372 iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > > > 373 void *data, struct iomap *iomap, struct iomap *srcmap) > > > 374 { > > > 375 struct iomap_dio *dio = data; > > > 376 > > > 377 switch (iomap->type) { > > > 378 case IOMAP_HOLE: > > > 379 if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) > > > 380 return -EIO; > > > 381 return iomap_dio_hole_actor(length, dio); > > > 382 case IOMAP_UNWRITTEN: > > > 383 if (!(dio->flags & IOMAP_DIO_WRITE)) > > > 384 return iomap_dio_hole_actor(length, dio); > > > 385 return iomap_dio_bio_actor(inode, pos, length, dio, iomap); > > > 386 case IOMAP_MAPPED: > > > 387 return iomap_dio_bio_actor(inode, pos, length, dio, iomap); > > > 388 case IOMAP_INLINE: > > > 389 return iomap_dio_inline_actor(inode, pos, length, dio, iomap); > > > 390 default: > > > 391 WARN_ON_ONCE(1); > > > 392 return -EIO; > > > 393 } > > > 394 } > > > > > > Could that be iomap->type == IOMAP_DELALLOC ? Looking throught the logs, > > > it contains a few pread64() calls until this happens, > > > > It _shouldn't_ be able to happen. XFS writes back ranges which exist > > in the page cache upon seeing an O_DIRECT I/O. So it's not supposed to > > be possible for there to be an extent which is waiting for the contents > > of the page cache to be written back. > > Okay, it is IOMAP_DELALLOC. We have, Can you share the fuzzer? If we end up with delalloc space here we probably need to fix a bug in the cache invalidation code.