FAILED: patch "[PATCH] ext4: add missing error check in __ext4_new_inode()" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-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 <[email protected]>.

thanks,

greg k-h

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

From: Theodore Ts'o <[email protected]>
Date: Sun, 10 Dec 2017 23:44:11 -0500
Subject: [PATCH] ext4: add missing error check in __ext4_new_inode()

It's possible for ext4_get_acl() to return an ERR_PTR. So we need to add a check for this case in __ext4_new_inode(). Otherwise on an error we can end up oops the kernel.

This was getting triggered by xfstests generic/388, which is a test which exercises the shutdown code path.

index b4267d72f249..b32cf263750d 100644
@@ -816,6 +816,8 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 #ifdef CONFIG_EXT4_FS_POSIX_ACL
 		struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
 
+		if (IS_ERR(p))
+			return ERR_CAST(p);
 		if (p) {
 			int acl_size = p->a_count * sizeof(ext4_acl_entry);