lkml.org 
[lkml]   [2021]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] mm/hugetlb: Fix use after free when subpool max_hpages accounting is not enabled
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.

\
 
 \ /
  Last update: 2021-01-28 01:19    [W:0.040 / U:0.596 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site