linux-kernel - Re: [patch 11/13] cpufreq/sparc-us3: Replace racy task affinity logic

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]

Date:   Thu, 13 Apr 2017 08:18:27 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Sebastian Siewior <bigeasy@...utronix.de>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        "David S. Miller" <davem@...emloft.net>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Len Brown <lenb@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, Tejun Heo <tj@...nel.org>,
        Tony Luck <tony.luck@...el.com>, linux-pm@...r.kernel.org
Subject: Re: [patch 11/13] cpufreq/sparc-us3: Replace racy task affinity logic

On 12-04-17, 22:07, Thomas Gleixner wrote:
> The access to the safari config register in the CPU frequency functions
> must be executed on the target CPU. This is achieved by temporarily setting
> the affinity of the calling user space thread to the requested CPU and
> reset it to the original affinity afterwards.
> 
> That's racy vs. CPU hotplug and concurrent affinity settings for that
> thread resulting in code executing on the wrong CPU and overwriting the
> new affinity setting.
> 
> Replace it by a straight forward smp function call. 
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Viresh Kumar <viresh.kumar@...aro.org>
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: linux-pm@...r.kernel.org
> ---
>  drivers/cpufreq/sparc-us3-cpufreq.c |   46 ++++++++++++------------------------
>  1 file changed, 16 insertions(+), 30 deletions(-)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh