The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a8867f4e3809050571c98de7a2d465aff5e4daf5 Mon Sep 17 00:00:00 2001

From: Phillip Potter phil@philpotter.co.uk Date: Mon, 12 Apr 2021 08:38:37 +0100 Subject: [PATCH] ext4: fix memory leak in ext4_mb_init_backend on error path.

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: Phillip Potter phil@philpotter.co.uk Cc: stable@kernel.org Link: https://lore.kernel.org/r/20210412073837.1686-1-phil@philpotter.co.uk Signed-off-by: Theodore Ts'o tytso@mit.edu

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 3239e6669e84..c2c22c2baac0 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3217,7 +3217,7 @@ 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));