4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Kan Liang <kan.li...@linux.intel.com> [ Upstream commit 82d71ed0277efc45360828af8c4e4d40e1b45352 ] The PMU is disabled in intel_pmu_handle_irq(), but cpuc->enabled is not updated accordingly. This is fine in current usage because no-one checks it - but fix it for future code: for example, the drain_pebs() will be modified to fix an auto-reload bug. Properly save/restore the old PMU state. Signed-off-by: Kan Liang <kan.li...@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Stephane Eranian <eran...@google.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Vince Weaver <vincent.wea...@maine.edu> Cc: a...@kernel.org Cc: kernel test robot <fengguang...@intel.com> Link: http://lkml.kernel.org/r/6f44ee84-56f8-79f1-559b-08e371eae...@linux.intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Sasha Levin <alexander.le...@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/x86/events/intel/core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2201,16 +2201,23 @@ static int intel_pmu_handle_irq(struct p int bit, loops; u64 status; int handled; + int pmu_enabled; cpuc = this_cpu_ptr(&cpu_hw_events); /* + * Save the PMU state. + * It needs to be restored when leaving the handler. + */ + pmu_enabled = cpuc->enabled; + /* * No known reason to not always do late ACK, * but just in case do it opt-in. */ if (!x86_pmu.late_ack) apic_write(APIC_LVTPC, APIC_DM_NMI); intel_bts_disable_local(); + cpuc->enabled = 0; __intel_pmu_disable_all(); handled = intel_pmu_drain_bts_buffer(); handled += intel_bts_interrupt(); @@ -2320,7 +2327,8 @@ again: done: /* Only restore PMU state when it's active. See x86_pmu_disable(). */ - if (cpuc->enabled) + cpuc->enabled = pmu_enabled; + if (pmu_enabled) __intel_pmu_enable_all(0, true); intel_bts_enable_local();
