Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751454AbcCKKN0 (ORCPT ); Fri, 11 Mar 2016 05:13:26 -0500 Received: from mga01.intel.com ([192.55.52.88]:29573 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbcCKKNN (ORCPT ); Fri, 11 Mar 2016 05:13:13 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,320,1455004800"; d="scan'208";a="64190118" From: Alexander Shishkin To: Peter Zijlstra , mingo@kernel.org, eranian@google.com Cc: linux-kernel@vger.kernel.org, vince@deater.net, dvyukov@google.com, andi@firstfloor.org, jolsa@redhat.com, panand@redhat.com, sasha.levin@oracle.com, oleg@redhat.com, Borislav Petkov Subject: Re: [PATCH 00/12] perf: more fixes In-Reply-To: <20160310143924.GR6356@twins.programming.kicks-ass.net> References: <20160224174539.570749654@infradead.org> <20160310143924.GR6356@twins.programming.kicks-ass.net> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Fri, 11 Mar 2016 12:12:56 +0200 Message-ID: <87r3fh8grb.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1135 Lines: 34 Peter Zijlstra writes: > On Wed, Feb 24, 2016 at 06:45:39PM +0100, Peter Zijlstra wrote: > >> With these patches syz-kaller can still trigger some fail; most notably some >> NMI watchdog triggers and a very sporadic unthrottle bug (much like last time). > > So the below seems to make the sporadic unthrottle thing much less > likely in that I haven't seen it in several hours, my machine keeps > dying on NMI watchdog bits. > > Boris, who has been running syz-kaller on AMD hardware and was hitting a > very similar bug with the AMD-IBS code, says its not fixed it for him, > so maybe there's still more to find. > > --- > Subject: perf: Fix unthrottle > > Its possible to IOC_PERIOD while the event is throttled, this would > re-start the event and the next tick would then try to unthrottle it, > and find the event wasn't actually stopped anymore. > > This would tickle a WARN in the x86-pmu code which isn't expecting to > start a !stopped event. > > Signed-off-by: Peter Zijlstra (Intel) FWIW, Reviewed-by: Alexander Shishkin Cheers, -- Alex