Re: [patch V2 00/24] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem

[Mark Rutland]

On Tue, Apr 25, 2017 at 07:28:38PM +0200, Sebastian Siewior wrote:
> On 2017-04-25 17:10:37 [+0100], Mark Rutland wrote:
> > When we bring the secondary CPU online, we detect an erratum that wasn't
> > present on the boot CPU, and try to enable a static branch we use to
> > track the erratum. The call to static_branch_enable() blows up as above.
> 
> this (cpus_set_cap()) seems only to be used used in CPU up part.
> 
> > I see that we now have static_branch_disable_cpuslocked(), but we don't
> > have an equivalent for enable. I'm not sure what we should be doing
> > here.
> 
> We should introduce static_branch_enable_cpuslocked(). Does this work
> for you (after s/static_branch_enable/static_branch_enable_cpuslocked/
> in cpus_set_cap()) ?:

The patch you linked worked for me, given the below patch for arm64 to
make use of static_branch_enable_cpuslocked().

Catalin/Will, are you happy for this to go via the tip tree with the
other hotplug locking changes?

Thanks,
Mark.

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