linux-kernel - Re: [RFC PATCH] mm: Enable khugepaged to operate on non-writable VMAs

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: <e52cac79-fe1a-401e-9259-747a4d587bd1@arm.com>
Date: Mon, 1 Sep 2025 20:56:04 +0530
From: Dev Jain <dev.jain@....com>
To: David Hildenbrand <david@...hat.com>, akpm@...ux-foundation.org,
 kas@...nel.org, willy@...radead.org, hughd@...gle.com
Cc: ziy@...dia.com, baolin.wang@...ux.alibaba.com,
 lorenzo.stoakes@...cle.com, Liam.Howlett@...cle.com, npache@...hat.com,
 ryan.roberts@....com, baohua@...nel.org, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] mm: Enable khugepaged to operate on non-writable VMAs


On 01/09/25 2:02 pm, David Hildenbrand wrote:
> On 01.09.25 09:48, Dev Jain wrote:
>>
>> @@ -19,7 +19,7 @@
>>       EM( SCAN_PTE_NON_PRESENT,    "pte_non_present")        \
>>       EM( SCAN_PTE_UFFD_WP,        "pte_uffd_wp")            \
>>       EM( SCAN_PTE_MAPPED_HUGEPAGE, "pte_mapped_hugepage")        \
>> -    EM( SCAN_PAGE_RO,        "no_writable_page")        \
>> +    EM( SCAN_PAGE_RO,        "no_writable_page") /* deprecated */    \
>>       EM( SCAN_LACK_REFERENCED_PAGE, "lack_referenced_page")        \
>>       EM( SCAN_PAGE_NULL,        "page_null")            \
>>       EM( SCAN_SCAN_ABORT,        "scan_aborted")            \
>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
>> index 4ec324a4c1fe..5ef8482597a9 100644
>> --- a/mm/khugepaged.c
>> +++ b/mm/khugepaged.c
>> @@ -39,7 +39,7 @@ enum scan_result {
>>       SCAN_PTE_NON_PRESENT,
>>       SCAN_PTE_UFFD_WP,
>>       SCAN_PTE_MAPPED_HUGEPAGE,
>> -    SCAN_PAGE_RO,
>> +    SCAN_PAGE_RO,    /* deprecated */
>
> Why can't we remove that completely.

(I raised this query in the other mail but due to not snipping stuff in 
between,

it may have been glossed over)

I was wondering whether a userspace script could break which assumes 
scan_page_ro

metric is there? I played with tracing long time back so I don't remember.


>
>