From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
tonyj@suse.com, nelson.dsouza@intel.com
Subject: Re: [PATCH 1/8] perf/x86/intel: Fix memory corruption
Date: Wed, 20 Mar 2019 23:22:20 +0100 [thread overview]
Message-ID: <20190320222220.GA2490@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CABPqkBQgmT+V29+eD6_rABzNBCo-R22N3PvPX4rWxSWEC0wPPg@mail.gmail.com>
On Wed, Mar 20, 2019 at 01:47:28PM -0700, Stephane Eranian wrote:
> Right now, if I do:
>
> echo 0 > /sys/bus/event_source/devices/cpu/allow_tsx_force_abort
>
> Then I don't have the guarantee on when there will be no abort when I
> return from the echo. the MSR is accessed only on PMU scheduling. I
> would expect a sysadmin to want some guarantee if this is to be
> switched on/off at runtime. If not, then having a boot time option is
> better in my opinion.
Something like cycling the nmi watchdog or:
perf stat -a -e cycles sleep 1
should be enough to force reschedule the events on every CPU.
Again, I'm not adverse to 'fixing' this if it can be done with limited
LoC. But I don't really see this as critical.
> This other bit I noticed is that cpuc->tfa_shadow is used to avoid the
> wrmsr(), but I don't see the code that makes sure the init value (0)
> matches the value of the MSR. Is this MSR guarantee to be zero on
> reset?
That was my understanding.
> How about on kexec()?
Good point, we might want to fix that.
next prev parent reply other threads:[~2019-03-20 22:22 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-14 13:01 [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Peter Zijlstra
2019-03-14 13:01 ` [PATCH 1/8] perf/x86/intel: Fix memory corruption Peter Zijlstra
2019-03-15 11:29 ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2019-03-19 6:29 ` [PATCH 1/8] " Stephane Eranian
2019-03-19 11:05 ` Peter Zijlstra
2019-03-19 17:52 ` Stephane Eranian
2019-03-19 18:20 ` Peter Zijlstra
2019-03-20 20:47 ` Stephane Eranian
2019-03-20 20:52 ` Stephane Eranian
2019-03-20 22:22 ` Peter Zijlstra [this message]
2019-03-21 12:38 ` Peter Zijlstra
2019-03-21 16:45 ` Thomas Gleixner
2019-03-21 17:10 ` Peter Zijlstra
2019-03-21 17:17 ` Thomas Gleixner
2019-03-21 18:20 ` Peter Zijlstra
2019-03-21 19:42 ` Tony Jones
2019-03-21 19:47 ` DSouza, Nelson
2019-03-21 20:07 ` Peter Zijlstra
2019-03-21 23:16 ` DSouza, Nelson
2019-03-22 22:14 ` DSouza, Nelson
2019-03-21 17:23 ` Stephane Eranian
2019-03-21 17:51 ` Thomas Gleixner
2019-03-22 19:04 ` Stephane Eranian
2019-04-03 7:32 ` Peter Zijlstra
2019-04-03 10:40 ` [tip:perf/urgent] perf/x86/intel: Initialize TFA MSR tip-bot for Peter Zijlstra
2019-04-03 11:30 ` Thomas Gleixner
2019-04-03 12:23 ` Vince Weaver
2019-03-14 13:01 ` [RFC][PATCH 2/8] perf/x86/intel: Simplify intel_tfa_commit_scheduling() Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 3/8] perf/x86: Simplify x86_pmu.get_constraints() interface Peter Zijlstra
2019-03-19 21:21 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT_COMMITTED Peter Zijlstra
2019-03-19 20:48 ` Stephane Eranian
2019-03-19 21:00 ` Peter Zijlstra
2019-03-20 13:14 ` Peter Zijlstra
2019-03-20 12:23 ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 5/8] perf/x86/intel: Optimize intel_get_excl_constraints() Peter Zijlstra
2019-03-19 23:43 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 6/8] perf/x86: Clear ->event_constraint[] on put Peter Zijlstra
2019-03-19 21:50 ` Stephane Eranian
2019-03-20 12:25 ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 7/8] perf/x86: Optimize x86_schedule_events() Peter Zijlstra
2019-03-19 23:55 ` Stephane Eranian
2019-03-20 13:11 ` Peter Zijlstra
2019-03-20 19:30 ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 8/8] perf/x86: Add sanity checks to x86_schedule_events() Peter Zijlstra
2019-03-15 7:15 ` [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Stephane Eranian
2019-03-15 7:15 ` Stephane Eranian
2019-03-15 8:01 ` Peter Zijlstra
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