Re: [PATCH] hwmon: (fam15h_power) Disable preemption when reading registers

From: Guenter Roeck
Date: Wed Jun 01 2016 - 14:15:27 EST

On Wed, Jun 01, 2016 at 03:41:26PM +0200, Borislav Petkov wrote:
> On Wed, Jun 01, 2016 at 06:22:59AM -0700, Guenter Roeck wrote:
> > An explanation would be helpful. Is this a bug fix ?
> That's a good point - yes, it is necessary. Both smp_processor_id()
> *and* smp_call_function_many() need to be called with preemption
> disabled.
> It did fire the BUG thing in check_preemption_disabled() with 4.7-rc1
> here without those fixes.
It would be great if you can add at least part of the BUG message as well
as a Fixes: tag into the patch description. If you had, I would not have
asked, saving both of us time ;-).

> But, we need the other patch too -
> "[PATCH] x86/cpu/AMD: Extend X86_FEATURE_TOPOEXT workaround to newer models"
> because the cpumask generation in read_registers() doesn't work on those
> Carrizo CPUs.
> IINM, the breakage came in during this merge window so we don't have to
> CC:stable but both should be sent to Linus as fixes for 4.7.
> You could sync with Ingo who takes/acks what... but they could go
> through tip and hwmon tree too, I don't see a hard dependency between
> the two - they'd only need to be in 4.7-final.

Sounds like separate trees should be fine then.