| From e0a5b188c5da8d878039312efc1ea6b8dbf754d7 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 15 May 2024 09:28:57 +0100 |
| Subject: ext4: fix infinite loop when replaying fast_commit |
| |
| From: Luis Henriques (SUSE) <luis.henriques@linux.dev> |
| |
| [ Upstream commit 907c3fe532253a6ef4eb9c4d67efb71fab58c706 ] |
| |
| When doing fast_commit replay an infinite loop may occur due to an |
| uninitialized extent_status struct. ext4_ext_determine_insert_hole() does |
| not detect the replay and calls ext4_es_find_extent_range(), which will |
| return immediately without initializing the 'es' variable. |
| |
| Because 'es' contains garbage, an integer overflow may happen causing an |
| infinite loop in this function, easily reproducible using fstest generic/039. |
| |
| This commit fixes this issue by unconditionally initializing the structure |
| in function ext4_es_find_extent_range(). |
| |
| Thanks to Zhang Yi, for figuring out the real problem! |
| |
| Fixes: 8016e29f4362 ("ext4: fast commit recovery path") |
| Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev> |
| Reviewed-by: Zhang Yi <yi.zhang@huawei.com> |
| Link: https://patch.msgid.link/20240515082857.32730-1-luis.henriques@linux.dev |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/ext4/extents_status.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c |
| index f37e62546745b..be3b3ccbf70b6 100644 |
| --- a/fs/ext4/extents_status.c |
| +++ b/fs/ext4/extents_status.c |
| @@ -312,6 +312,8 @@ void ext4_es_find_extent_range(struct inode *inode, |
| ext4_lblk_t lblk, ext4_lblk_t end, |
| struct extent_status *es) |
| { |
| + es->es_lblk = es->es_len = es->es_pblk = 0; |
| + |
| if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) |
| return; |
| |
| -- |
| 2.43.0 |
| |
