FAILED: patch "[PATCH] ext4: fix leaking sysfs kobject after failed mount" 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 cb8d53d2c97369029cc638c9274ac7be0a316c75 Mon Sep 17 00:00:00 2001
From: Eric Biggers <[email protected]>
Date: Tue, 22 Sep 2020 09:24:56 -0700
Subject: [PATCH] ext4: fix leaking sysfs kobject after failed mount

ext4_unregister_sysfs() only deletes the kobject. The reference to it needs to be put separately, like ext4_put_super() does.

This addresses the syzbot report
"memory leak in kobject_set_name_vargs (3)"
(https://syzkaller.appspot.com/bug?extid=9f864abad79fae7c17e1).

index ea425b49b345..41953b86ffe3 100644
@@ -4872,6 +4872,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
 failed_mount8:
 	ext4_unregister_sysfs(sb);
+	kobject_put(&sbi->s_kobj);
 failed_mount7:
 	ext4_unregister_li_request(sb);
 failed_mount6:

Hi Greg,

Here is the backport. This will apply to both v4.9.y and v4.4.y.

--
Regards
Sudip

From 4be70a405c3a30c8602ea7a6c58b31f905e34106 Mon Sep 17 00:00:00 2001
From: Eric Biggers <[email protected]>
Date: Tue, 22 Sep 2020 09:24:56 -0700
Subject: [PATCH] ext4: fix leaking sysfs kobject after failed mount

commit cb8d53d2c97369029cc638c9274ac7be0a316c75 upstream

ext4_unregister_sysfs() only deletes the kobject. The reference to it needs to be put separately, like ext4_put_super() does.

This addresses the syzbot report
"memory leak in kobject_set_name_vargs (3)"
(https://syzkaller.appspot.com/bug?extid=9f864abad79fae7c17e1).

---
 fs/ext4/super.c | 1 +
 1 file changed, 1 insertion(+)

index 00391db0064b..84d28d3efc60 100644
@@ -4336,6 +4336,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_QUOTA
 failed_mount8:
 	ext4_unregister_sysfs(sb);
+	kobject_put(&sbi->s_kobj);
 #endif
 failed_mount7:
 	ext4_unregister_li_request(sb);

2.11.0

Now applied, thanks.

greg k-h