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

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Message-ID: <20161118123325.GA15416@krava>
Date:   Fri, 18 Nov 2016 13:33:25 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     "Liang, Kan" <kan.liang@...el.com>,
        Andi Kleen <andi@...stfloor.org>,
        Vince Weaver <vince@...ter.net>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] perf/x86/uncore: Allow single pmu/box within events group

On Fri, Nov 18, 2016 at 12:28:50PM +0100, Peter Zijlstra wrote:
> 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.

yep, that's what's happening now.. but after the event_init callback

jirka