From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vince@deater.net>
Cc: mingo@kernel.org, alexander.shishkin@linux.intel.com,
eranian@google.com, linux-kernel@vger.kernel.org,
dvyukov@google.com, andi@firstfloor.org, jolsa@redhat.com,
panand@redhat.com, sasha.levin@oracle.com, oleg@redhat.com,
Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH 00/12] perf: more fixes
Date: Fri, 11 Mar 2016 15:23:46 +0100 [thread overview]
Message-ID: <20160311142346.GE6344@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.11.1603100943060.7775@pianoman.cluster.toy>
On Thu, Mar 10, 2016 at 09:44:30AM -0500, Vince Weaver wrote:
> On Thu, 10 Mar 2016, Peter Zijlstra wrote:
>
> > On Wed, Feb 24, 2016 at 06:45:39PM +0100, Peter Zijlstra wrote:
> >
> > 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.
>
> sorry I am not being much help with this big syz-kaller bug hunt, but I
> just wanted to chime in that there's a (probably the same) long standing
> IBS bug that perf_fuzzer hits all the time too, it was bad enough
> that I had to stop running perf_fuzzer on my AMD box.
The below seems to fix the IBS issue tickled by syz-kaller on my
machine. I've not yet ran perf-fuzzer, which seems able to tickle a
different set of bugs.
---
Subject: perf, amb: Fix IBS throttle
When the IBS IRQ handler get a !0 return from perf_event_overflow;
meaning it should throttle the event, it only disables it, it doesn't
call perf_ibs_stop().
This confuses the state machine, as we'll use pmu::start() ->
perf_ibs_start() to unthrottle.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/events/amd/ibs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 51087c29b2c2..7956d29762ef 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -599,7 +599,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
throttle = perf_event_overflow(event, &data, ®s);
out:
if (throttle)
- perf_ibs_disable_event(perf_ibs, hwc, *config);
+ perf_ibs_stop(event, 0);
else
perf_ibs_enable_event(perf_ibs, hwc, period >> 4);
next prev parent reply other threads:[~2016-03-11 14:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-24 17:45 [PATCH 00/12] perf: more fixes Peter Zijlstra
2016-02-24 17:45 ` [PATCH 01/12] perf: Close install vs exit race Peter Zijlstra
2016-02-25 8:03 ` [tip:perf/urgent] perf: Close install vs. " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 02/12] perf: Do not double free Peter Zijlstra
2016-02-25 8:04 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 03/12] perf: Allow perf_release() with !event->ctx Peter Zijlstra
2016-02-25 8:04 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 04/12] perf: Only update context time when active Peter Zijlstra
2016-02-25 8:04 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 05/12] perf: Fix cloning Peter Zijlstra
2016-02-25 8:05 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 06/12] perf: Fix race between event install and jump_labels Peter Zijlstra
2016-02-25 8:05 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 07/12] perf: Cure event->pending_disable race Peter Zijlstra
2016-02-25 8:06 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 08/12] perf: Introduce EVENT_TIME Peter Zijlstra
2016-02-25 8:06 ` [tip:perf/urgent] perf: Fix ctx time tracking by introducing EVENT_TIME tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 09/12] perf: Fix scaling vs enable_on_exec Peter Zijlstra
2016-02-25 8:07 ` [tip:perf/urgent] perf: Fix scaling vs. perf_event_enable_on_exec() tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 10/12] perf: Fix scaling vs perf_event_enable Peter Zijlstra
2016-02-25 8:07 ` [tip:perf/urgent] perf: Fix scaling vs. perf_event_enable() tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 11/12] perf: Fix scaling vs perf_install_in_context Peter Zijlstra
2016-02-25 8:07 ` [tip:perf/urgent] perf: Fix scaling vs. perf_install_in_context() tip-bot for Peter Zijlstra
2016-02-24 17:45 ` [PATCH 12/12] perf: Robustify task_function_call() Peter Zijlstra
2016-02-25 8:08 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2016-03-10 14:39 ` [PATCH 00/12] perf: more fixes Peter Zijlstra
2016-03-10 14:44 ` Vince Weaver
2016-03-11 14:23 ` Peter Zijlstra [this message]
2016-03-11 15:41 ` Borislav Petkov
2016-03-21 9:49 ` [tip:perf/urgent] perf/x86/ibs: Fix IBS throttle tip-bot for Peter Zijlstra
2016-03-15 15:38 ` [PATCH 00/12] perf: more fixes Peter Zijlstra
2016-03-16 22:59 ` Peter Zijlstra
2016-03-16 23:10 ` Peter Zijlstra
2016-03-17 11:54 ` Borislav Petkov
2016-03-11 10:12 ` Alexander Shishkin
2016-03-21 9:48 ` [tip:perf/urgent] perf/core: Fix the unthrottle logic tip-bot for Peter Zijlstra
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