ext4: fix memory leak in ext4_mb_init_backend on error path.

stable inclusion
from stable-5.10.43
commit 2050c6e5b161e5e25ce3c420fef58b24fa388a49
bugzilla: 109284
CVE: NA

--------------------------------

commit a8867f4e upstream.

Fix a memory leak discovered by syzbot when a file system is corrupted
with an illegally large s_log_groups_per_flex.

Reported-by: syzbot+aa12d6106ea4ca1b6aae@syzkaller.appspotmail.com
Signed-off-by: NPhillip Potter <phil@philpotter.co.uk>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20210412073837.1686-1-phil@philpotter.co.ukSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/ext4/mballoc.c

@@ -2738,7 +2738,7 @@ 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));