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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20161118132346.GA17918@krava>
Date:   Fri, 18 Nov 2016 14:23:46 +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 01:53:54PM +0100, Peter Zijlstra wrote:
> On Fri, Nov 18, 2016 at 01:33:25PM +0100, Jiri Olsa wrote:
> > 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
> 
> Ah yes indeed. Its the is_uncore_event() test in uncore_collect_event()
> that's too lenient, that allows us to mix events from various uncore
> boxes.
> 
> Would something like so fix things too? Because that is the point of
> is_uncore_event() in collect(), to only collect events for _that_ pmu.

that looks ok.. I'll run the test 

jirka