Re: [PATCH v4 3/9] arm: perf: save/resore pmsel

On 01/08/2019 14:01, Will Deacon wrote:

[typo in subject: resore ->restore]

On Wed, Jul 17, 2019 at 09:17:06AM +0100, Julien Thierry wrote:

...

The callback pmu->read() can be called with interrupts enabled. Currently, on ARM, this can cause the following callchain:

armpmu_read() -> armpmu_event_update() -> armv7pmu_read_counter()

Why can't we just disable irqs in armv7pmu_read_counter() ?

We could. But since we get rid of the lock after (otherwise it is the only reason we have to keep the lock) we might as well find another solution.

Thanks,