linux-kernel - Re: [PATCH 2/2] mm: compaction: fix the possible deadlock when isolating hugetlb pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 14 Mar 2023 10:27:25 -0700
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc:     akpm@...ux-foundation.org, mgorman@...hsingularity.net,
        osalvador@...e.de, vbabka@...e.cz, william.lam@...edance.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] mm: compaction: fix the possible deadlock when
 isolating hugetlb pages

On 03/14/23 12:11, Baolin Wang wrote:
> On 3/14/2023 1:08 AM, Mike Kravetz wrote:
> > On 03/13/23 18:37, Baolin Wang wrote:
> > 
> > It would seem that the pfn of a hugetlb page would always be a multiple of
> > COMPACT_CLUSTER_MAX so we would drop the lock.  However, I am not sure if
> > that is ALWAYS true and would prefer something like the code you suggested.
> 
> Well, this is not always true, suppose the CONT-PTE hugetlb on ARM arch,
> which contains 16 contiguous normal pages.
> 

Right.  I keep forgetting about the CONT-* page sizes on arm :(

In any case, I think explicitly dropping the lock as you have done is a
good idea.

Feel free to add,

Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
-- 
Mike Kravetz