Re: [PATCH] cpufreq: Fix NULL reference crash while accessing policy->governor_data

From: Juri Lelli
Date: Thu Jan 28 2016 - 05:44:05 EST

On 28/01/16 07:45, Viresh Kumar wrote:
> On 27-01-16, 23:54, Rafael J. Wysocki wrote:
> > So I've applied this, but I'm not sure it is sufficient yet.
> At least, this solves the crash Juri was hitting on a multi cluster
> box.
> > Have you double checked whether or not stuff cannot be reordered by
> > the CPU and/or the compiler and no additional memory barriers are needed?
> I don't think CPU will reorder things before a function call. It can
> reorder lines, which CPU thinks aren't related but it can't assume the
> same in this case. We have tons of code like this.
> @Juri: What do you say?

Yeah, it looks good on my boxes (even though I'll run some more tests
later today). I'm not entirely sure either about the reordering, but
reordering across a function call (of a different compilation unit)
seems quite unlikely to me as well.


- Juri