linux-kernel - Re: [PATCH 02/10] perf/x86: Improve HT workaround GP counter constraint

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]

Date:	Fri, 22 May 2015 15:25:14 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Vince Weaver <vincent.weaver@...ne.edu>,
	Jiri Olsa <jolsa@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 02/10] perf/x86: Improve HT workaround GP counter
 constraint

On Fri, May 22, 2015 at 06:05:49AM -0700, Stephane Eranian wrote:
> > I bet you tested the exclusive events earlier :-) Its one of the bugs,
> > the n_excl accounting is leaking up. Once !0 it stays !0.
> 
> So you're saying intel_put_excl_constraint() does not do the --n_excl?

No it does, but we call get_events_constraints() every time we do
x86_schedule_events(), and put_events_constraints() only on
x86_pmu_del(). This means we call get() much more than we put().

Therefore leak up.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/