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 5A694C001DE for ; Fri, 11 Aug 2023 03:42:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232916AbjHKDm1 (ORCPT ); Thu, 10 Aug 2023 23:42:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231509AbjHKDmU (ORCPT ); Thu, 10 Aug 2023 23:42:20 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6161F211B; Thu, 10 Aug 2023 20:42:19 -0700 (PDT) Received: from canpemm500010.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4RMTzX1D4JzCrcK; Fri, 11 Aug 2023 11:38:48 +0800 (CST) Received: from huawei.com (10.175.127.227) by canpemm500010.china.huawei.com (7.192.105.118) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Fri, 11 Aug 2023 11:42:17 +0800 From: Ye Bin To: , CC: , Ye Bin Subject: [PATCH 1/2] ext2: fix race between setxattr and write back Date: Fri, 11 Aug 2023 11:38:56 +0800 Message-ID: <20230811033857.1800578-2-yebin10@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230811033857.1800578-1-yebin10@huawei.com> References: <20230811033857.1800578-1-yebin10@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500010.china.huawei.com (7.192.105.118) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There's a issue as follows: Block Allocation Reservation Windows Map (ext2_try_to_allocate_with_rsv): reservation window 0x000000006f105382 start: 0, end: 0 reservation window 0x000000008fd1a555 start: 1044, end: 1059 Window map complete. kernel BUG at fs/ext2/balloc.c:1158! invalid opcode: 0000 [#1] PREEMPT SMP KASAN RIP: 0010:ext2_try_to_allocate_with_rsv.isra.0+0x15c4/0x1800 Call Trace: ext2_new_blocks+0x935/0x1690 ext2_new_block+0x73/0xa0 ext2_xattr_set2+0x74f/0x1730 ext2_xattr_set+0x12b6/0x2260 ext2_xattr_user_set+0x9c/0x110 __vfs_setxattr+0x139/0x1d0 __vfs_setxattr_noperm+0xfc/0x370 __vfs_setxattr_locked+0x205/0x2c0 vfs_setxattr+0x19d/0x3b0 do_setxattr+0xff/0x220 setxattr+0x123/0x150 path_setxattr+0x193/0x1e0 __x64_sys_setxattr+0xc8/0x170 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Above issue may happens as follows: setxattr write back ext2_xattr_set ext2_xattr_set2 ext2_new_block ext2_new_blocks ext2_try_to_allocate_with_rsv alloc_new_reservation --> group=0 [0, 1023] rsv [1016, 1023] do_writepages mpage_writepages write_cache_pages __mpage_writepage ext2_get_block ext2_get_blocks ext2_alloc_branch ext2_new_blocks ext2_try_to_allocate_with_rsv alloc_new_reservation -->group=1 [1024, 2047] rsv [1044, 1059] if ((my_rsv->rsv_start > group_last_block) || (my_rsv->rsv_end < group_first_block) rsv_window_dump BUG(); Now ext2 mkwrite delay allocate new blocks. So there maybe allocate blocks when do write back. However, there is no concurrent protection between ext2_xattr_set() and do_writepages(). To solve about issue hold '&ei->truncate_mutex' lock when new block for xattr. Signed-off-by: Ye Bin --- fs/ext2/balloc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c index c8049c90323d..039f655febfd 100644 --- a/fs/ext2/balloc.c +++ b/fs/ext2/balloc.c @@ -1432,8 +1432,14 @@ ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal, ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp) { unsigned long count = 1; + struct ext2_inode_info *ei = EXT2_I(inode); + ext2_fsblk_t ret; + + mutex_lock(&ei->truncate_mutex); + ret = ext2_new_blocks(inode, goal, &count, errp); + mutex_unlock(&ei->truncate_mutex); - return ext2_new_blocks(inode, goal, &count, errp); + return ret; } #ifdef EXT2FS_DEBUG -- 2.31.1