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 A9B4EC0015E for ; Fri, 21 Jul 2023 19:23:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232180AbjGUTXA (ORCPT ); Fri, 21 Jul 2023 15:23:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232179AbjGUTW7 (ORCPT ); Fri, 21 Jul 2023 15:22:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE0C31727 for ; Fri, 21 Jul 2023 12:22:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7AE6461D76 for ; Fri, 21 Jul 2023 19:22:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E712C433C9; Fri, 21 Jul 2023 19:22:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689967377; bh=i8UTBl3mjBQ0/x6L3xSnQkIlQSHH35Ae/pt/60VrIPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PeR2WlqxBiMHmxVrmi/MjdrNk4trcCOO6H3Ta5vaSLMqkcGVszZiF6iLgrbwztxLj CtiP5n8YHcsoyoo2uNhKRKeesuj4DUCUlfEDLv07VbhgU8cVKVACd6+dty00/hFXq1 Nblixqw8qlY8ciexfS4jiszvUi7GmGkbp46nRLfE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Darrick J. Wong" , "Ritesh Harjani (IBM)" , Jan Kara Subject: [PATCH 6.1 113/223] ext2/dax: Fix ext2_setsize when len is page aligned Date: Fri, 21 Jul 2023 18:06:06 +0200 Message-ID: <20230721160525.689090100@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160520.865493356@linuxfoundation.org> References: <20230721160520.865493356@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ritesh Harjani (IBM) commit fcced95b6ba2a507a83b8b3e0358a8ac16b13e35 upstream. PAGE_ALIGN(x) macro gives the next highest value which is multiple of pagesize. But if x is already page aligned then it simply returns x. So, if x passed is 0 in dax_zero_range() function, that means the length gets passed as 0 to ->iomap_begin(). In ext2 it then calls ext2_get_blocks -> max_blocks as 0 and hits bug_on here in ext2_get_blocks(). BUG_ON(maxblocks == 0); Instead we should be calling dax_truncate_page() here which takes care of it. i.e. it only calls dax_zero_range if the offset is not page/block aligned. This can be easily triggered with following on fsdax mounted pmem device. dd if=/dev/zero of=file count=1 bs=512 truncate -s 0 file [79.525838] EXT2-fs (pmem0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk [79.529376] ext2 filesystem being mounted at /mnt1/test supports timestamps until 2038 (0x7fffffff) [93.793207] ------------[ cut here ]------------ [93.795102] kernel BUG at fs/ext2/inode.c:637! [93.796904] invalid opcode: 0000 [#1] PREEMPT SMP PTI [93.798659] CPU: 0 PID: 1192 Comm: truncate Not tainted 6.3.0-rc2-xfstests-00056-g131086faa369 #139 [93.806459] RIP: 0010:ext2_get_blocks.constprop.0+0x524/0x610 <...> [93.835298] Call Trace: [93.836253] [93.837103] ? lock_acquire+0xf8/0x110 [93.838479] ? d_lookup+0x69/0xd0 [93.839779] ext2_iomap_begin+0xa7/0x1c0 [93.841154] iomap_iter+0xc7/0x150 [93.842425] dax_zero_range+0x6e/0xa0 [93.843813] ext2_setsize+0x176/0x1b0 [93.845164] ext2_setattr+0x151/0x200 [93.846467] notify_change+0x341/0x4e0 [93.847805] ? lock_acquire+0xf8/0x110 [93.849143] ? do_truncate+0x74/0xe0 [93.850452] ? do_truncate+0x84/0xe0 [93.851739] do_truncate+0x84/0xe0 [93.852974] do_sys_ftruncate+0x2b4/0x2f0 [93.854404] do_syscall_64+0x3f/0x90 [93.855789] entry_SYSCALL_64_after_hwframe+0x72/0xdc CC: stable@vger.kernel.org Fixes: 2aa3048e03d3 ("iomap: switch iomap_zero_range to use iomap_iter") Reviewed-by: Darrick J. Wong Signed-off-by: Ritesh Harjani (IBM) Signed-off-by: Jan Kara Message-Id: <046a58317f29d9603d1068b2bbae47c2332c17ae.1682069716.git.ritesh.list@gmail.com> Signed-off-by: Greg Kroah-Hartman --- fs/ext2/inode.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -1265,9 +1265,8 @@ static int ext2_setsize(struct inode *in inode_dio_wait(inode); if (IS_DAX(inode)) - error = dax_zero_range(inode, newsize, - PAGE_ALIGN(newsize) - newsize, NULL, - &ext2_iomap_ops); + error = dax_truncate_page(inode, newsize, NULL, + &ext2_iomap_ops); else error = block_truncate_page(inode->i_mapping, newsize, ext2_get_block);