linux-kernel - Re: [PATCH v3 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] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250806163532.82466-1-sj@kernel.org>
Date: Wed,  6 Aug 2025 09:35:32 -0700
From: SeongJae Park <sj@...nel.org>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: SeongJae Park <sj@...nel.org>,
	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
Subject: Re: [PATCH v3 3/3] fs/proc/task_mmu: execute PROCMAP_QUERY ioctl under per-vma locks

On Wed,  6 Aug 2025 08:59:04 -0700 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>


Thanks,
SJ

[...]