From: Miaohe Lin <linmiaohe@huawei.com>
Date: Wed, 24 Feb 2021 20:06:50 +0000 (-0800)
Subject: mm/hugetlb: fix potential double free in hugetlb_register_node() error path
X-Git-Tag: v4.4.259~35
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6fd892537ab459787d217b35855b974dc2fc0bbe;p=thirdparty%2Fkernel%2Fstable.git

mm/hugetlb: fix potential double free in hugetlb_register_node() error path

[ Upstream commit cc2205a67dec5a700227a693fc113441e73e4641 ]

In hugetlb_sysfs_add_hstate(), we would do kobject_put() on hstate_kobjs
when failed to create sysfs group but forget to set hstate_kobjs to NULL.
Then in hugetlb_register_node() error path, we may free it again via
hugetlb_unregister_node().

Link: https://lkml.kernel.org/r/20210107123249.36964-1-linmiaohe@huawei.com
Fixes: a3437870160c ("hugetlb: new sysfs interface")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <smuchun@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dc877712ef1f3..7c3ecac8aeb3f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2485,8 +2485,10 @@ static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
 		return -ENOMEM;
 
 	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
-	if (retval)
+	if (retval) {
 		kobject_put(hstate_kobjs[hi]);
+		hstate_kobjs[hi] = NULL;
+	}
 
 	return retval;
 }