+ mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm/hugetlb: fix potential double free in hugetlb_register_node() error path
has been added to the -mm tree.  Its filename is
     mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path.patch

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------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
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/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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- a/mm/hugetlb.c~mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path
+++ a/mm/hugetlb.c
@@ -2947,8 +2947,10 @@ 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;
 }
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

mm-vmallocc-fix-potential-memory-leak.patch
mm-hugetlb-fix-potential-missing-huge-page-size-info.patch
mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path.patch