Re: [tip:perf/urgent] perf/x86/intel: Fix PMI handling for Intel PT

From: Peter Zijlstra
Date: Wed Jun 24 2015 - 08:21:44 EST


On Fri, Jun 19, 2015 at 10:58:36AM -0700, tip-bot for Alexander Shishkin wrote:
> Commit-ID: 1b7b938f181742f899a2f31c280f79dabef6ddb6
> Gitweb: http://git.kernel.org/tip/1b7b938f181742f899a2f31c280f79dabef6ddb6
> Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> AuthorDate: Tue, 9 Jun 2015 13:03:26 +0300
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> CommitDate: Fri, 19 Jun 2015 09:38:47 +0200
>
> perf/x86/intel: Fix PMI handling for Intel PT

And the price goes to....

The result is very reproducible and the bisection is good, as reverting
this one commit makes it go away.

I've just finished, have not actually looked at the code yet, I need to
eat first.

---

root@ivb-ep:/usr/src/linux-2.6# perf record -a -e cycles:pp -- make
O=defconfig-build/ clean; make O=defconfig-build/ defconfig; make
O=defconfig-build/ -j80 -s

results in fail:

[ 45.618402] Uhhuh. NMI received for unknown reason 21 on CPU 0.
[ 45.625020] Do you have a strange power saving mode enabled?
[ 45.631336] Dazed and confused, but trying to continue
[ 49.736011] Uhhuh. NMI received for unknown reason 31 on CPU 3.
[ 49.742627] Do you have a strange power saving mode enabled?
[ 49.748954] Dazed and confused, but trying to continue
[ 50.317877] Uhhuh. NMI received for unknown reason 31 on CPU 26.
[ 50.324591] Do you have a strange power saving mode enabled?
[ 50.330917] Dazed and confused, but trying to continue
[ 50.950088] Uhhuh. NMI received for unknown reason 31 on CPU 27.
[ 50.956804] Do you have a strange power saving mode enabled?
[ 50.963129] Dazed and confused, but trying to continue


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