[BUG] sleeping function called from invalid context in perf_pmu_register()

On Fri, Dec 29, 2017 at 09:59:04AM +0100, Corentin Labbe wrote:

SNIP

[    1.494884] Exception stack(0xee845fb0 to 0xee845ff8)
[    1.499933] 5fa0:                                     00000000 00000000 00000000 00000000
[    1.508100] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    1.516267] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    1.522871]  r5:c06c2528 r4:00000000

This is due to get_cpu() in cci_pmu_probe() in drivers/bus/arm-cci.c which disable preemption.
But now I do not know how to fix it.
My .config is below.

yep, looks like cci_pmu_probe needs to be fixed.. can't
call perf_pmu_register with preemption disabled

jirka