linux-kernel - Re: [PATCH v3 1/2] mm: migration: fix the FOLL

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]

Message-ID: <878rnqe074.fsf@yhuang6-desk2.ccr.corp.intel.com>
Date:   Mon, 15 Aug 2022 09:59:27 +0800
From:   "Huang, Ying" <ying.huang@...el.com>
To:     Haiyue Wang <haiyue.wang@...el.com>
Cc:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <akpm@...ux-foundation.org>, <david@...hat.com>,
        <linmiaohe@...wei.com>, <songmuchun@...edance.com>,
        <naoya.horiguchi@...ux.dev>, <alex.sierra@....com>
Subject: Re: [PATCH v3 1/2] mm: migration: fix the FOLL_GET failure on
 following huge page

Haiyue Wang <haiyue.wang@...el.com> writes:

> Not all huge page APIs support FOLL_GET option, so the __NR_move_pages

move_pages() is a syscall, so you can just call it move_pages(), or
move_pages() syscall.

> will fail to get the page node information for huge page.
                                                 ~~~~~~~~~
some huge pages?

> This is an temporary solution to mitigate the racing fix.

Why is it "racing fix"?  This isn't a race condition fix.

Best Regards,
Huang, Ying

> After supporting follow huge page by FOLL_GET is done, this fix can be
> reverted safely.
>
> Fixes: 4cd614841c06 ("mm: migration: fix possible do_pages_stat_array racing with memory offline")
> Signed-off-by: Haiyue Wang <haiyue.wang@...el.com>

[snip]