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From:   Phillip Potter <phil@philpotter.co.uk>
To:     tytso@mit.edu
Cc:     adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] fs: ext4: mballoc: amend goto to cleanup groupinfo memory correctly
Date:   Mon, 12 Apr 2021 08:38:37 +0100
Message-Id: <20210412073837.1686-1-phil@philpotter.co.uk>
MIME-Version: 1.0
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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@syzkaller.appspotmail.com
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
---
 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