From: Namhyung Kim namhyung@kernel.org
[ Upstream commit 5debf02131227d39988e44adf5090fb796fa8466 ]
The commit 3966c3feca3f ("x86/perf/amd: Remove need to check "running" bit in NMI handler") introduced this. It seems x86_pmu_stop can be called recursively (like when it losts some samples) like below:
x86_pmu_stop intel_pmu_disable_event (x86_pmu_disable) intel_pmu_pebs_disable intel_pmu_drain_pebs_nhm (x86_pmu_drain_pebs_buffer) x86_pmu_stop
While commit 35d1ce6bec13 ("perf/x86/intel/ds: Fix x86_pmu_stop warning for large PEBS") fixed it for the normal cases, there's another path to call x86_pmu_stop() recursively when a PEBS error was detected (like two or more counters overflowed at the same time).
Like in the Kan's previous fix, we can skip the interrupt accounting for large PEBS, so check the iregs which is set for PMI only.
Fixes: 3966c3feca3f ("x86/perf/amd: Remove need to check "running" bit in NMI handler") Reported-by: John Sperbeck jsperbeck@google.com Suggested-by: Peter Zijlstra peterz@infradead.org Signed-off-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lkml.kernel.org/r/20201126110922.317681-1-namhyung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/events/intel/ds.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index 404315df1e167..4c84b87904930 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1937,7 +1937,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs) if (error[bit]) { perf_log_lost_samples(event, error[bit]);
- if (perf_event_account_interrupt(event)) + if (iregs && perf_event_account_interrupt(event)) x86_pmu_stop(event, 0); }