stable inclusion from linux-4.19.198 commit 5485fe228f9771190de24f8936c43879fa52fc25 -------------------------------- commit 8f6840c4fd1e7bd715e403074fb161c1a04cda73 upstream. After commit c89128a00838 ("ext4: handle errors on ext4_commit_super"), 'ret' may be set to 0 before calling ext4_fill_flex_info(), if ext4_fill_flex_info() fails ext4_mount() doesn't return error code, it makes 'root' is null which causes crash in legacy_get_tree(). Fixes: c89128a00838 ("ext4: handle errors on ext4_commit_super") Reported-by: Hulk Robot <hulkci@huawei.com> Cc: <stable@vger.kernel.org> # v4.18+ Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Link: https://lore.kernel.org/r/20210510111051.55650-1-yangyingliang@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/ext4/super.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index f8e419ba9f0de..d793e597c0623 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4713,6 +4713,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) ext4_msg(sb, KERN_ERR, "unable to initialize " "flex_bg meta info!"); + ret = -ENOMEM; goto failed_mount6; } -- 2.25.1