Linus,
please pull the latest perf/urgent branch from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
perf-urgent-2020-12-06
up to: fc17db8aa4c5: perf/x86/intel: Check PEBS status correctly
Two fixes for performance monitoring on X86:
- Add recursion protection to another callchain invoked from
x86_pmu_stop() which can recurse back into x86_pmu_stop(). The first
attempt to fix this missed this extra code path.
- Use the already filtered status variable to check for PEBS counter
overflow bits and not the unfiltered full status read from
IA32_PERF_GLOBAL_STATUS which can have unrelated bits check which
would be evaluated incorrectly.
Thanks,
tglx
------------------>
Namhyung Kim (1):
perf/x86/intel: Fix a warning on x86_pmu_stop() with large PEBS
Stephane Eranian (1):
perf/x86/intel: Check PEBS status correctly
arch/x86/events/intel/ds.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index b47cc4226934..485c5066f8b8 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1916,7 +1916,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
*iregs, struct perf_sample_d
* 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;
@@ -1940,7 +1940,7 @@ static void intel_pmu_drain_pebs_nhm(struct pt_regs
*iregs, struct perf_sample_d
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);
}
