From: Stephane Eranian <[email protected]> [ Upstream commit fc17db8aa4c53cbd2d5469bb0521ea0f0a6dbb27 ]
The kernel cannot disambiguate when 2+ PEBS counters overflow at the same time. This is what the comment for this code suggests. However, I see the comparison is done with the unfiltered p->status which is a copy of IA32_PERF_GLOBAL_STATUS at the time of the sample. This register contains more than the PEBS counter overflow bits. It also includes many other bits which could also be set. Signed-off-by: Namhyung Kim <[email protected]> Signed-off-by: Stephane Eranian <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Sasha Levin <[email protected]> --- 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..cf12e5a956f7e 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1913,7 +1913,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs) * that caused the PEBS record. It's called collision. * If collision happened, the record will be dropped. */ - if (p->status != (1ULL << bit)) { + if (pebs_status != (1ULL << bit)) { for_each_set_bit(i, (unsigned long *)&pebs_status, size) error[i]++; continue; -- 2.27.0
