From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 854476FA0 for ; Mon, 16 Jan 2023 16:55:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D6FAC433D2; Mon, 16 Jan 2023 16:55:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673888113; bh=XFhvJXdSBgcBzSrrZaPb5g/AH/WaNju3I+z4Yk9RLrM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TsGJmNSldK7+4BnhveRsUE7ZGUjgbkmzxagvn5weSdL7kSKQDJDcpdQXkrDapF8rU kXH4RTD+VDbr7FxKzZVlNxDdcggczfA8s36KWnHyt0O4JexAraztGXtHDo+2iDKJfb UFOxdbkzX79oe63cOKzwrGKsBBbmKhIANM25RmpY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Baokun Li , "Ritesh Harjani (IBM)" , Theodore Tso Subject: [PATCH 4.19 406/521] ext4: add inode table check in __ext4_get_inode_loc to aovid possible infinite loop Date: Mon, 16 Jan 2023 16:51:08 +0100 Message-Id: <20230116154905.250556496@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154847.246743274@linuxfoundation.org> References: <20230116154847.246743274@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Baokun Li commit eee22187b53611e173161e38f61de1c7ecbeb876 upstream. In do_writepages, if the value returned by ext4_writepages is "-ENOMEM" and "wbc->sync_mode == WB_SYNC_ALL", retry until the condition is not met. In __ext4_get_inode_loc, if the bh returned by sb_getblk is NULL, the function returns -ENOMEM. In __getblk_slow, if the return value of grow_buffers is less than 0, the function returns NULL. When the three processes are connected in series like the following stack, an infinite loop may occur: do_writepages <--- keep retrying ext4_writepages mpage_map_and_submit_extent mpage_map_one_extent ext4_map_blocks ext4_ext_map_blocks ext4_ext_handle_unwritten_extents ext4_ext_convert_to_initialized ext4_split_extent ext4_split_extent_at __ext4_ext_dirty __ext4_mark_inode_dirty ext4_reserve_inode_write ext4_get_inode_loc __ext4_get_inode_loc <--- return -ENOMEM sb_getblk __getblk_gfp __getblk_slow <--- return NULL grow_buffers grow_dev_page <--- return -ENXIO ret = (block < end_block) ? 1 : -ENXIO; In this issue, bg_inode_table_hi is overwritten as an incorrect value. As a result, `block < end_block` cannot be met in grow_dev_page. Therefore, __ext4_get_inode_loc always returns '-ENOMEM' and do_writepages keeps retrying. As a result, the writeback process is in the D state due to an infinite loop. Add a check on inode table block in the __ext4_get_inode_loc function by referring to ext4_read_inode_bitmap to avoid this infinite loop. Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Ritesh Harjani (IBM) Link: https://lore.kernel.org/r/20220817132701.3015912-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4663,9 +4663,17 @@ static int __ext4_get_inode_loc(struct i inodes_per_block = EXT4_SB(sb)->s_inodes_per_block; inode_offset = ((inode->i_ino - 1) % EXT4_INODES_PER_GROUP(sb)); - block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block); iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb); + block = ext4_inode_table(sb, gdp); + if ((block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) || + (block >= ext4_blocks_count(EXT4_SB(sb)->s_es))) { + ext4_error(sb, "Invalid inode table block %llu in " + "block_group %u", block, iloc->block_group); + return -EFSCORRUPTED; + } + block += (inode_offset / inodes_per_block); + bh = sb_getblk(sb, block); if (unlikely(!bh)) return -ENOMEM;