linux-kernel - Re: [PATCH v5 4/7] mm: Introduce FPB_RESPECT

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 for Android: free password hash cracker in your pocket

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

Message-ID: <6963114B-A7F2-49AA-83CA-CC4EE284714F@nvidia.com>
Date: Wed, 23 Jul 2025 11:28:57 -0400
From: Zi Yan <ziy@...dia.com>
To: Dev Jain <dev.jain@....com>
Cc: akpm@...ux-foundation.org, ryan.roberts@....com, david@...hat.com,
 willy@...radead.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
 catalin.marinas@....com, will@...nel.org, Liam.Howlett@...cle.com,
 lorenzo.stoakes@...cle.com, vbabka@...e.cz, jannh@...gle.com,
 anshuman.khandual@....com, peterx@...hat.com, joey.gouly@....com,
 ioworker0@...il.com, baohua@...nel.org, kevin.brodsky@....com,
 quic_zhenhuah@...cinc.com, christophe.leroy@...roup.eu,
 yangyicong@...ilicon.com, linux-arm-kernel@...ts.infradead.org,
 hughd@...gle.com, yang@...amperecomputing.com
Subject: Re: [PATCH v5 4/7] mm: Introduce FPB_RESPECT_WRITE for PTE batching
 infrastructure

On 18 Jul 2025, at 5:02, Dev Jain wrote:

> Patch 6 optimizes mprotect() by batch clearing the ptes, masking in the new

“Patch 6” might not make sense when reading it in the git log. Something like
below might be better:

mprotect() will be optimized by batch clearing the ptes, masking in the new
protections, and batch setting the ptes in an upcoming commit.

No need to repin for this one.

> protections, and batch setting the ptes. Suppose that the first pte
> of the batch is writable - with the current implementation of
> folio_pte_batch(), it is not guaranteed that the other ptes in the batch
> are already writable too, so we may incorrectly end up setting the
> writable bit on all ptes via modify_prot_commit_ptes().
>
> Therefore, introduce FPB_RESPECT_WRITE so that all ptes in the batch
> are writable or not.
>
> Signed-off-by: Dev Jain <dev.jain@....com>
> ---
>  mm/internal.h | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>

LGTM. Reviewed-by: Zi Yan <ziy@...dia.com>

Best Regards,
Yan, Zi