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perf/x86/intel, watchdog/core: Sanitize PMU HT bug workaround

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The lockup_detector_suspend/resume() interface is broken in several ways
especially as it results in recursive locking of the CPU hotplug lock.

Use the new stop/restart interface in the perf NMI watchdog to temporarily
disable and reenable the already active watchdog events. That's enough to
handle it.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194146.247141871@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2017-09-12 21:36:56 +02:00 committed by Ingo Molnar
parent d0b6e0a8ef
commit 2406e3b166
1 changed files with 4 additions and 7 deletions
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11
arch/x86/events/intel/core.c
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@ -4409,10 +4409,9 @@ static __init int fixup_ht_bug(void)
return 0;
}
if (lockup_detector_suspend() != 0) {
pr_debug("failed to disable PMU erratum BJ122, BV98, HSD29 workaround\n");
return 0;
}
cpus_read_lock();
hardlockup_detector_perf_stop();
x86_pmu.flags &= ~(PMU_FL_EXCL_CNTRS | PMU_FL_EXCL_ENABLED);
@ -4420,9 +4419,7 @@ static __init int fixup_ht_bug(void)
x86_pmu.commit_scheduling = NULL;
x86_pmu.stop_scheduling = NULL;
lockup_detector_resume();
cpus_read_lock();
hardlockup_detector_perf_restart();
for_each_online_cpu(c)
free_excl_cntrs(c);