Re: [PATCH] perf/x86/uncore: Allow single pmu/box within events group

From: Peter Zijlstra
Date: Fri Nov 18 2016 - 06:28:58 EST

On Fri, Nov 18, 2016 at 01:15:28AM +0100, Jiri Olsa wrote:
> Current uncore_validate_group code expects all events within
> the group to have same pmu.
> This leads to constraint code using wrong boxes which leads
> in my case to touching uninitialized spinlocks, but could
> be probably worse.. depends on type and box details.
> I get lockdep warning below for following perf stat:
> # perf stat -vv -e '{uncore_cbox_0/config=0x0334/,uncore_qpi_0/event=1/}' -a sleep 1

Hurm, we shouldn't be allowing that in the first place I think.

Let me stare at the generic group code, the intent was to only allow
software events to mix with hw events, nothing else.