[PATCH] fs: ext4: mballoc: amend goto to cleanup groupinfo memory correctly

From: Phillip Potter
Date: Mon Apr 12 2021 - 03:38:45 EST


When flexible block groups are enabled on a filesystem, and there are
too many log groups per flexible block group, goto err_freebuddy rather
than err_freesgi within ext4_mb_init_backend. Cleanup code for new_inode
and successive executions of ext4_mb_add_groupinfo in the previous loop
is then correctly run. Fixes memory leak reported by syzbot at:
https://syzkaller.appspot.com/bug?extid=aa12d6106ea4ca1b6aae

Reported-by: syzbot+aa12d6106ea4ca1b6aae@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Phillip Potter <phil@xxxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a02fadf4fc84..d24cb3dc79ff 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2715,7 +2715,7 @@ static int ext4_mb_init_backend(struct super_block *sb)
*/
if (sbi->s_es->s_log_groups_per_flex >= 32) {
ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group");
- goto err_freesgi;
+ goto err_freebuddy;
}
sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex,
BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9));
--
2.30.2