| Message ID | 20240515082857.32730-1-luis.henriques@linux.dev |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] ext4: fix infinite loop when replaying fast_commit | expand |
On 2024/5/15 16:28, Luis Henriques (SUSE) wrote: > 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> Thanks for fixing this issue，looks good to me. Reviewed-by: Zhang Yi <yi.zhang@huawei.com> > --- > 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 4a00e2f019d9..3a53dbb85e15 100644 > --- a/fs/ext4/extents_status.c > +++ b/fs/ext4/extents_status.c > @@ -310,6 +310,8 @@ 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; > >
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index 4a00e2f019d9..3a53dbb85e15 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -310,6 +310,8 @@ 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;
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> --- fs/ext4/extents_status.c | 2 ++ 1 file changed, 2 insertions(+)