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

From: Borislav Petkov
Date: Wed Jun 01 2016 - 09:41:43 EST

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

It did fire the BUG thing in check_preemption_disabled() with 4.7-rc1
here without those fixes.

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.



ECO tip #101: Trim your mails when you reply.