| From a2c2f0826e2b75560b31daf1cd9a755ab93cf4c6 Mon Sep 17 00:00:00 2001 |
| From: Hou Tao <houtao1@huawei.com> |
| Date: Fri, 20 Aug 2021 12:45:05 +0800 |
| Subject: ext4: limit the number of blocks in one ADD_RANGE TLV |
| |
| From: Hou Tao <houtao1@huawei.com> |
| |
| commit a2c2f0826e2b75560b31daf1cd9a755ab93cf4c6 upstream. |
| |
| Now EXT4_FC_TAG_ADD_RANGE uses ext4_extent to track the |
| newly-added blocks, but the limit on the max value of |
| ee_len field is ignored, and it can lead to BUG_ON as |
| shown below when running command "fallocate -l 128M file" |
| on a fast_commit-enabled fs: |
| |
| kernel BUG at fs/ext4/ext4_extents.h:199! |
| invalid opcode: 0000 [#1] SMP PTI |
| CPU: 3 PID: 624 Comm: fallocate Not tainted 5.14.0-rc6+ #1 |
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) |
| RIP: 0010:ext4_fc_write_inode_data+0x1f3/0x200 |
| Call Trace: |
| ? ext4_fc_write_inode+0xf2/0x150 |
| ext4_fc_commit+0x93b/0xa00 |
| ? ext4_fallocate+0x1ad/0x10d0 |
| ext4_sync_file+0x157/0x340 |
| ? ext4_sync_file+0x157/0x340 |
| vfs_fsync_range+0x49/0x80 |
| do_fsync+0x3d/0x70 |
| __x64_sys_fsync+0x14/0x20 |
| do_syscall_64+0x3b/0xc0 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| Simply fixing it by limiting the number of blocks |
| in one EXT4_FC_TAG_ADD_RANGE TLV. |
| |
| Fixes: aa75f4d3daae ("ext4: main fast-commit commit path") |
| Cc: stable@kernel.org |
| Signed-off-by: Hou Tao <houtao1@huawei.com> |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Link: https://lore.kernel.org/r/20210820044505.474318-1-houtao1@huawei.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| fs/ext4/fast_commit.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| --- a/fs/ext4/fast_commit.c |
| +++ b/fs/ext4/fast_commit.c |
| @@ -832,6 +832,12 @@ static int ext4_fc_write_inode_data(stru |
| sizeof(lrange), (u8 *)&lrange, crc)) |
| return -ENOSPC; |
| } else { |
| + unsigned int max = (map.m_flags & EXT4_MAP_UNWRITTEN) ? |
| + EXT_UNWRITTEN_MAX_LEN : EXT_INIT_MAX_LEN; |
| + |
| + /* Limit the number of blocks in one extent */ |
| + map.m_len = min(max, map.m_len); |
| + |
| fc_ext.fc_ino = cpu_to_le32(inode->i_ino); |
| ex = (struct ext4_extent *)&fc_ext.fc_ex; |
| ex->ee_block = cpu_to_le32(map.m_lblk); |