Messages in this thread | | | Date | Wed, 27 Jan 2021 16:17:55 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] mm/hugetlb: Fix use after free when subpool max_hpages accounting is not enabled |
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On Wed, 27 Jan 2021 10:08:22 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:
> On 2021/1/27 8:06, Mike Kravetz wrote: > > On 1/26/21 3:55 AM, Miaohe Lin wrote: > >> When subpool max_hpages accounting is not enabled, used_hpages is always 0 > >> and might lead to release subpool prematurely because it indicates no pages > >> are used now while there might be. > > > > It might be good to say that you need min_hpages accounting (min_size mount > > option) enabled for this issue to occur. Or, perhaps say this is possible > > if a hugetlbfs filesystem is created with the min_size option and without > > the size option. > > > > That might better explain the conditions in which a user could see the issue. > > So commit log might looks like this ? > """ > If a hugetlbfs filesystem is created with the min_size option and without > the size option, used_hpages is always 0 and might lead to release subpool > prematurely because it indicates no pages are used now while there might > be. > > In order to fix this issue, we should check used_hpages == 0 iff max_hpages > accounting is enabled. As max_hpages accounting should be enabled in most > common case, this is not worth a Cc stable. > """ > > If so, should I send a V2 or Andrew would kindly do this? > Many thanks.
I made that change, thanks.
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