linux-kernel - [PATCH] ext4: fix leaking sysfs kobject after failed mount

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Date:   Tue, 22 Sep 2020 09:24:56 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-ext4@...r.kernel.org, Theodore Ts'o <tytso@....edu>
Cc:     syzkaller-bugs@...glegroups.com, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org,
        syzbot+9f864abad79fae7c17e1@...kaller.appspotmail.com
Subject: [PATCH] ext4: fix leaking sysfs kobject after failed mount

From: Eric Biggers <ebiggers@...gle.com>

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).

Reported-by: syzbot+9f864abad79fae7c17e1@...kaller.appspotmail.com
Fixes: 72ba74508b28 ("ext4: release sysfs kobject when failing to enable quotas on mount")
Cc: stable@...r.kernel.org
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 fs/ext4/super.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ea425b49b345..41953b86ffe3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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:

base-commit: ba4f184e126b751d1bffad5897f263108befc780
-- 
2.28.0