linux-kernel - Re: [PATCH 5/6] mm/hugetlb: fix sysfs group leak in hugetlb_unregister

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Message-ID: <b44ef13c-c9df-5d08-f92f-649fef9d74ee@intel.com>
Date:   Wed, 17 Aug 2022 17:41:39 +0800
From:   "Yin, Fengwei" <fengwei.yin@...el.com>
To:     Miaohe Lin <linmiaohe@...wei.com>, <akpm@...ux-foundation.org>,
        <mike.kravetz@...cle.com>, <songmuchun@...edance.com>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/6] mm/hugetlb: fix sysfs group leak in
 hugetlb_unregister_node()

Hi Miaohe,

On 8/16/2022 9:05 PM, Miaohe Lin wrote:
> }
>  
>  	if (h->demote_order) {
> -		if (sysfs_create_group(hstate_kobjs[hi],
> -					&hstate_demote_attr_group))
> +		retval = sysfs_create_group(hstate_kobjs[hi],
> +					    &hstate_demote_attr_group);
What about add one more:
   just return if hstate_attr_group creating failed:

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0aee2f3ae15c..a67ef4b4eb3f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3845,6 +3845,7 @@ static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
        if (retval) {
                kobject_put(hstate_kobjs[hi]);
                hstate_kobjs[hi] = NULL;
+               return retval;
        }

Once hstate_kobjs[hi] is set to NULL, hstate_demote_attr_group creating will
fail as well. Thanks.


Regards
Yin, Fengwei

> +		if (retval) {
>  			pr_warn("HugeTLB unable to create demote interfaces for %s\n", h->name);
> +			sysfs_remove_group(hstate_kobjs[hi], hstate_attr_group);
> +			kobject_put(hstate_kobjs[hi]);
> +			hstate_kobjs[hi] = NULL;
> +			return retval;
> +		}
>  	}