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

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>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 905a7d5..dd56e20 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2988,8 +2988,10 @@ 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;
 }