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authorPeter Zijlstra <peterz@infradead.org>2017-09-12 21:36:56 +0200
committerIngo Molnar <mingo@kernel.org>2017-09-14 11:41:03 +0200
commit2406e3b166eee42777a6b0b38f52f924454474d7 (patch)
tree955877e11ae1214cf8ed504c616457e70d671299 /arch
parentwatchdog/hardlockup: Provide interface to stop/restart perf events (diff)
downloadlinux-2406e3b166eee42777a6b0b38f52f924454474d7.tar.xz
linux-2406e3b166eee42777a6b0b38f52f924454474d7.zip
perf/x86/intel, watchdog/core: Sanitize PMU HT bug workaround
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/events/intel/core.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 829e89cfcee2..9fb9a1f1e47b 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -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);