linux-kernel - Re: [PATCH v4 3/3] fs/proc/task_mmu: execute PROCMAP

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: <CAEf4BzaRgFid5WDsNGOzE=ysc6jPcSAmB0MwRHYdtSbm-vLrWQ@mail.gmail.com>
Date: Mon, 11 Aug 2025 16:14:58 -0700
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: akpm@...ux-foundation.org, Liam.Howlett@...cle.com, 
	lorenzo.stoakes@...cle.com, david@...hat.com, vbabka@...e.cz, 
	peterx@...hat.com, jannh@...gle.com, hannes@...xchg.org, mhocko@...nel.org, 
	paulmck@...nel.org, shuah@...nel.org, adobriyan@...il.com, brauner@...nel.org, 
	josef@...icpanda.com, yebin10@...wei.com, linux@...ssschuh.net, 
	willy@...radead.org, osalvador@...e.de, andrii@...nel.org, 
	ryan.roberts@....com, christophe.leroy@...roup.eu, tjmercier@...gle.com, 
	kaleshsingh@...gle.com, aha310510@...il.com, linux-kernel@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, 
	linux-kselftest@...r.kernel.org, SeongJae Park <sj@...nel.org>
Subject: Re: [PATCH v4 3/3] fs/proc/task_mmu: execute PROCMAP_QUERY ioctl
 under per-vma locks

On Fri, Aug 8, 2025 at 8:29 AM Suren Baghdasaryan <surenb@...gle.com> wrote:
>
> Utilize per-vma locks to stabilize vma after lookup without taking
> mmap_lock during PROCMAP_QUERY ioctl execution. If vma lock is
> contended, we fall back to mmap_lock but take it only momentarily
> to lock the vma and release the mmap_lock. In a very unlikely case
> of vm_refcnt overflow, this fall back path will fail and ioctl is
> done under mmap_lock protection.
>
> This change is designed to reduce mmap_lock contention and prevent
> PROCMAP_QUERY ioctl calls from blocking address space updates.
>
> Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
> Acked-by: SeongJae Park <sj@...nel.org>
> ---
>  fs/proc/task_mmu.c | 103 +++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 85 insertions(+), 18 deletions(-)
>

LGTM

Acked-by: Andrii Nakryiko <andrii@...nel.org>


[...]