[113/173] mm/hugetlb: fix potential double free in hugetlb_register_node() error path

Commit Message

Andrew Morton Feb. 24, 2021, 8:06 p.m. UTC

From: Miaohe Lin <[e-mail]>
Subject: 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/[e-mail]
Fixes: a3437870160c ("hugetlb: new sysfs interface")
Signed-off-by: Miaohe Lin <[e-mail]>
Reviewed-by: Mike Kravetz <[e-mail]>
Reviewed-by: Muchun Song <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/hugetlb.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Patch

--- a/mm/hugetlb.c~mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path
+++ a/mm/hugetlb.c
@@ -2988,8 +2988,10 @@  static int hugetlb_sysfs_add_hstate(stru
 		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;
 }