Re: [PATCH v1 2/2] x86, perf,cqm: handle CPU hotplug

Dave Hansen
2015-06-18T20:00:23Z

On 06/18/2015 12:47 PM, Thomas Gleixner wrote:
>> > @@ -1239,12 +1239,15 @@ static inline void cqm_pick_event_reader(int cpu)
>> > int phys_id = topology_physical_package_id(cpu);
>> > int i;
>> >
>> > + mutex_lock(&cache_mutex);
> I already explained it to Vikas. You CANNOT take a mutex in that code
> path as it runs with interrupts disabled on a CPU which cannot
> schedule.

How did lockdep not blow up and scream about this?