linux-kernel - Re: [PATCH v3 5/5] psi: introduce psi monitor

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: <20190129123843.GK28467@hirez.programming.kicks-ass.net>
Date:   Tue, 29 Jan 2019 13:38:44 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Suren Baghdasaryan <surenb@...gle.com>
Cc:     gregkh@...uxfoundation.org, tj@...nel.org, lizefan@...wei.com,
        hannes@...xchg.org, axboe@...nel.dk, dennis@...nel.org,
        dennisszhou@...il.com, mingo@...hat.com, akpm@...ux-foundation.org,
        corbet@....net, cgroups@...r.kernel.org, linux-mm@...ck.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-team@...roid.com
Subject: Re: [PATCH v3 5/5] psi: introduce psi monitor

On Thu, Jan 24, 2019 at 01:15:18PM -0800, Suren Baghdasaryan wrote:
> +			atomic_set(&group->polling, polling);
> +			/*
> +			 * Memory barrier is needed to order group->polling
> +			 * write before times[] read in collect_percpu_times()
> +			 */
> +			smp_mb__after_atomic();

That's broken, smp_mb__{before,after}_atomic() can only be used on
atomic RmW operations, something atomic_set() is _not_.