Re: [patch V2 12/13] cpufreq/sparc-us2e: Replace racy task affinity logic

[David Miller]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Thu, 13 Apr 2017 10:19:07 +0200 (CEST)

> spu_queue_register() needs to invoke setup functions on a particular
> 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 using work_on_cpu_safe() which guarantees to run the code on
> the requested CPU or to fail in case the CPU is offline.
> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>