linux-kernel - Re: [PATCH v3 tip/perf/core 1/4] mm: introduce mmap_lock_speculation

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: <20241024095659.GD9767@noisy.programming.kicks-ass.net>
Date: Thu, 24 Oct 2024 11:56:59 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: Andrii Nakryiko <andrii@...nel.org>, linux-trace-kernel@...r.kernel.org,
	linux-mm@...ck.org, oleg@...hat.com, rostedt@...dmis.org,
	mhiramat@...nel.org, bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org, jolsa@...nel.org, paulmck@...nel.org,
	willy@...radead.org, akpm@...ux-foundation.org, mjguzik@...il.com,
	brauner@...nel.org, jannh@...gle.com, mhocko@...nel.org,
	vbabka@...e.cz, shakeel.butt@...ux.dev, hannes@...xchg.org,
	Liam.Howlett@...cle.com, lorenzo.stoakes@...cle.com
Subject: Re: [PATCH v3 tip/perf/core 1/4] mm: introduce
 mmap_lock_speculation_{start|end}

On Wed, Oct 23, 2024 at 03:17:01PM -0700, Suren Baghdasaryan wrote:

> > Or better yet, just use seqcount...
> 
> Yeah, with these changes it does look a lot like seqcount now...
> I can take another stab at rewriting this using seqcount_t but one
> issue that Jann was concerned about is the counter being int vs long.
> seqcount_t uses unsigned, so I'm not sure how to address that if I
> were to use seqcount_t. Any suggestions how to address that before I
> move forward with a rewrite?

So if that issue is real, it is not specific to this case. Specifically
preemptible seqcount will be similarly affected. So we should probably
address that in the seqcount implementation.