linux-kernel - Re: [PATCH] mm/page_table_check: fix accessing unmapped ptep

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] [day] [month] [year] [list]

Message-ID: <fe21e0c9-50d3-0a4b-00b4-22a5dfd6711e@huawei.com>
Date:   Fri, 27 May 2022 09:10:53 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     Pasha Tatashin <pasha.tatashin@...een.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        <zhengqi.arch@...edance.com>, Matthew Wilcox <willy@...radead.org>
CC:     Matthew Wilcox <willy@...radead.org>,
        David Rientjes <rientjes@...gle.com>,
        linux-mm <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm/page_table_check: fix accessing unmapped ptep

On 2022/5/27 2:31, Pasha Tatashin wrote:
>>> Miaohe, please store the ptep, or maybe drop this patch entirely.
>>
>> I think it's best to fix it.  I rewrote the changelog as
>>
>> : ptep is unmapped too early, so ptep could theoretically be accessed while
>> : it's unmapped.  This might become a problem if/when CONFIG_HIGHPTE becomes
>> : available on riscv.
>> :
>> : Fix it by deferring pte_unmap() until page table checking is done.
>>
>> I'll retain the Fixes:.  This doesn't imply cc:stable in MM, and anyone
>> who backports the original patchset will want to know about this fixup.
> Makes sense.
> 
> 
>> And I queued a fixup for the thing Matthew noticed.
> Thank you Andrew.
> 

Many thanks for all of your comments, review and fixup! :)

> Pasha
> .
>