Messages in this thread | | | Subject | Re: [PATCH] hugetlb: fix hugetlb cgroup refcounting during mremap | From | Mike Kravetz <> | Date | Mon, 15 Nov 2021 15:25:23 -0800 |
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Subject: Re: [PATCH] hugetlb: fix hugetlb cgroup refcounting during mremap
To: Andrew Morton <akpm@linux-foundation.org>, Bui Quang Minh <minhquangbui99@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>, Michal Hocko <mhocko@suse.com>, Muchun Song <songmuchun@bytedance.com>, Mina Almasry <almasrymina@google.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org
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On 11/15/21 1:16 PM, Andrew Morton wrote:
> On Sat, 13 Nov 2021 22:44:10 +0700 Bui Quang Minh <minhquangbui99@gmail.com> wrote:
>
>> When hugetlb_vm_op_open() is called during copy_vma(), we may take the
>> reference to resv_map->css. Later, when clearing the reservation pointer
>> of old_vma after transferring it to new_vma, we forget to drop the
>> reference to resv_map->css. This leads to a reference leak of css.
>>
>> Fixes this by adding a check to drop reservation css reference in
>> clear_vma_resv_huge_pages()
Good catch! Sorry I missed this in my review.
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com
> Thanks. I added cc:stable to this (550a7d60bd5e35a was merged a year
> ago) and I've queued it for 5.16-rc2, pending suitable reviewer feedback.
I may be confused, but 550a7d60bd5e35a was just merged in 5.16-rc1 so
no need for cc:stable.
--
Mike Kravetz
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