[PATCH 23/29] perf session: Add byte-swap handler for PERF_RECORD_COMPRESSED2
From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: 2026-05-24 03:29:40
Also in:
lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
From: Arnaldo Carvalho de Melo <redacted>
PERF_RECORD_COMPRESSED2 events carry a data_size field that must be
byte-swapped when reading cross-endian perf.data files. Without a
swap handler, reading COMPRESSED2 events on a different-endian machine
would misinterpret data_size as a garbage value, causing the
decompression path to read the wrong number of bytes.
The compressed payload itself is a raw byte stream and needs no
swapping.
Fixes: 208c0e16834472bb ("perf record: Add 8-byte aligned event type PERF_RECORD_COMPRESSED2")
Reported-by: sashiko-bot@kernel.org # Running on a local machine
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chun-Tse Shao <redacted>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude Opus 4.6 (1M context) [off-list ref]
Signed-off-by: Arnaldo Carvalho de Melo <redacted>
---
tools/perf/util/session.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 04446f18d76c4cdb..cb1d851686d9cbc0 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c@@ -1045,6 +1045,14 @@ static int perf_event__time_conv_swap(union perf_event *event, return 0; } +static int perf_event__compressed2_swap(union perf_event *event, + bool sample_id_all __maybe_unused) +{ + /* Only data_size needs swapping — compressed payload is a raw byte stream */ + event->pack2.data_size = bswap_64(event->pack2.data_size); + return 0; +} + static int perf_event__bpf_metadata_swap(union perf_event *event, bool sample_id_all __maybe_unused) {
@@ -1186,6 +1194,7 @@ static perf_event__swap_op perf_event__swap_ops[] = { [PERF_RECORD_STAT_ROUND] = perf_event__stat_round_swap, [PERF_RECORD_EVENT_UPDATE] = perf_event__event_update_swap, [PERF_RECORD_TIME_CONV] = perf_event__time_conv_swap, + [PERF_RECORD_COMPRESSED2] = perf_event__compressed2_swap, [PERF_RECORD_BPF_METADATA] = perf_event__bpf_metadata_swap, [PERF_RECORD_SCHEDSTAT_CPU] = perf_event__schedstat_cpu_swap, [PERF_RECORD_SCHEDSTAT_DOMAIN] = perf_event__schedstat_domain_swap,
--
2.54.0