The following commit has been merged into the perf/core branch of tip:

Commit-ID:     f226805bc5f60adf03783d8e4cbfe303ccecd64e
Gitweb:        https://git.kernel.org/tip/f226805bc5f60adf03783d8e4cbfe303ccecd64e
Author:        Yabin Cui <yabinc@google.com>
AuthorDate:    Wed, 15 May 2024 12:36:08 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 19 Nov 2024 09:23:42 +01:00

perf/core: Check sample_type in perf_sample_save_callchain

Check sample_type in perf_sample_save_callchain() to prevent
saving callchain data when it isn't required.

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240515193610.2350456-3-yabinc@google.com
---
 arch/x86/events/amd/ibs.c  | 3 +--
 arch/x86/events/intel/ds.c | 6 ++----
 include/linux/perf_event.h | 5 +++++
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index c3a2f6f..f029396 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -1129,8 +1129,7 @@ fail:
 	 * recorded as part of interrupt regs. Thus we need to use rip from
 	 * interrupt regs while unwinding call stack.
 	 */
-	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-		perf_sample_save_callchain(&data, event, iregs);
+	perf_sample_save_callchain(&data, event, iregs);
 
 	throttle = perf_event_overflow(event, &data, &regs);
 out:
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 8afc4ad..4990a24 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1789,8 +1789,7 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
-		perf_sample_save_callchain(data, event, iregs);
+	perf_sample_save_callchain(data, event, iregs);
 
 	/*
 	 * We use the interrupt regs as a base because the PEBS record does not
@@ -1957,8 +1956,7 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
-		perf_sample_save_callchain(data, event, iregs);
+	perf_sample_save_callchain(data, event, iregs);
 
 	*regs = *iregs;
 	/* The ip in basic is EventingIP */
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index f7c0a3f..3ac202d 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1279,6 +1279,11 @@ static inline void perf_sample_save_callchain(struct perf_sample_data *data,
 {
 	int size = 1;
 
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
+		return;
+	if (WARN_ON_ONCE(data->sample_flags & PERF_SAMPLE_CALLCHAIN))
+		return;
+
 	data->callchain = perf_callchain(event, regs);
 	size += data->callchain->nr;