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 72919C38A2D for ; Wed, 26 Oct 2022 14:05:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234128AbiJZOFx (ORCPT ); Wed, 26 Oct 2022 10:05:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234117AbiJZOFv (ORCPT ); Wed, 26 Oct 2022 10:05:51 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA9B87E01E; Wed, 26 Oct 2022 07:05:49 -0700 (PDT) Received: from canpemm500004.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4My9W90kFWzJn7d; Wed, 26 Oct 2022 22:03:01 +0800 (CST) Received: from [10.174.179.14] (10.174.179.14) by canpemm500004.china.huawei.com (7.192.104.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 26 Oct 2022 22:05:47 +0800 Subject: Re: [PATCH v3 4/4] ext4: fix bug_on in __es_tree_search caused by bad boot loader inode To: Baokun Li , CC: , , , , , , References: <20221026042310.3839669-1-libaokun1@huawei.com> <20221026042310.3839669-5-libaokun1@huawei.com> From: Jason Yan Message-ID: <2c39db49-2800-d264-6433-48a6382878a4@huawei.com> Date: Wed, 26 Oct 2022 22:05:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20221026042310.3839669-5-libaokun1@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.14] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500004.china.huawei.com (7.192.104.92) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 2022/10/26 12:23, Baokun Li wrote: > We got a issue as fllows: > ================================================================== > kernel BUG at fs/ext4/extents_status.c:203! > invalid opcode: 0000 [#1] PREEMPT SMP > CPU: 1 PID: 945 Comm: cat Not tainted 6.0.0-next-20221007-dirty #349 > RIP: 0010:ext4_es_end.isra.0+0x34/0x42 > RSP: 0018:ffffc9000143b768 EFLAGS: 00010203 > RAX: 0000000000000000 RBX: ffff8881769cd0b8 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff8fc27cf7 RDI: 00000000ffffffff > RBP: ffff8881769cd0bc R08: 0000000000000000 R09: ffffc9000143b5f8 > R10: 0000000000000001 R11: 0000000000000001 R12: ffff8881769cd0a0 > R13: ffff8881768e5668 R14: 00000000768e52f0 R15: 0000000000000000 > FS: 00007f359f7f05c0(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f359f5a2000 CR3: 000000017130c000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > __es_tree_search.isra.0+0x6d/0xf5 > ext4_es_cache_extent+0xfa/0x230 > ext4_cache_extents+0xd2/0x110 > ext4_find_extent+0x5d5/0x8c0 > ext4_ext_map_blocks+0x9c/0x1d30 > ext4_map_blocks+0x431/0xa50 > ext4_mpage_readpages+0x48e/0xe40 > ext4_readahead+0x47/0x50 > read_pages+0x82/0x530 > page_cache_ra_unbounded+0x199/0x2a0 > do_page_cache_ra+0x47/0x70 > page_cache_ra_order+0x242/0x400 > ondemand_readahead+0x1e8/0x4b0 > page_cache_sync_ra+0xf4/0x110 > filemap_get_pages+0x131/0xb20 > filemap_read+0xda/0x4b0 > generic_file_read_iter+0x13a/0x250 > ext4_file_read_iter+0x59/0x1d0 > vfs_read+0x28f/0x460 > ksys_read+0x73/0x160 > __x64_sys_read+0x1e/0x30 > do_syscall_64+0x35/0x80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > ================================================================== > > In the above issue, ioctl invokes the swap_inode_boot_loader function to > swap inode<5> and inode<12>. However, inode<5> contain incorrect imode and > disordered extents, and i_nlink is set to 1. The extents check for inode in > the ext4_iget function can be bypassed bacause 5 is EXT4_BOOT_LOADER_INO. > While links_count is set to 1, the extents are not initialized in > swap_inode_boot_loader. After the ioctl command is executed successfully, > the extents are swapped to inode<12>, in this case, run the `cat` command > to view inode<12>. And Bug_ON is triggered due to the incorrect extents. > > When the boot loader inode is not initialized, its imode can be one of the > following: > 1) the imode is a bad type, which is marked as bad_inode in ext4_iget and > set to S_IFREG. > 2) the imode is good type but not S_IFREG. > 3) the imode is S_IFREG. > > The BUG_ON may be triggered by bypassing the check in cases 1 and 2. > Therefore, when the boot loader inode is bad_inode or its imode is not > S_IFREG, initialize the inode to avoid triggering the BUG. > > Signed-off-by: Baokun Li > --- > fs/ext4/ioctl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Looks good, Reviewed-by: Jason Yan