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Message-Id: <20220621152725.2668041-1-rsilvera@google.com>
Date: Tue, 21 Jun 2022 15:27:25 +0000
From: Raul Silvera <rsilvera@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Dave Marchevsky <davemarchevsky@...com>,
Adrian Hunter <adrian.hunter@...el.com>,
Colin Ian King <colin.king@...el.com>,
Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
Raul Silvera <rsilvera@...gle.com>
Cc: linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] perf: Adjust perf-inject output data offset for backward compatibility
When perf inject creates a new file, it reuses the data offset from the
input file. If there has been a change on the size of the header, as
happened in v5.12 -> v5.13, the new offsets will be wrong, resulting in
a corrupted output file.
This change adds the function perf_session__data_offset to compute the
data offset based on the current header size, and uses that instead of
the offset from the original input file.
Signed-off-by: Raul Silvera <rsilvera@...gle.com>
---
Changes since v1:
- Use the adjusted header->data_offset in do_write_header instead of
recomputing it.
---
tools/perf/builtin-inject.c | 2 +-
tools/perf/util/header.c | 14 ++++++++++++++
tools/perf/util/header.h | 2 ++
3 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index a75bf11585b5..1dfdcef36607 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -916,7 +916,7 @@ static int __cmd_inject(struct perf_inject *inject)
inject->tool.tracing_data = perf_event__repipe_tracing_data;
}
- output_data_offset = session->header.data_offset;
+ output_data_offset = perf_session__data_offset(session->evlist);
if (inject->build_id_all) {
inject->tool.mmap = perf_event__repipe_buildid_mmap;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 53332da100e8..6ad629db63b7 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3686,6 +3686,20 @@ int perf_session__write_header(struct perf_session *session,
return perf_session__do_write_header(session, evlist, fd, at_exit, NULL);
}
+size_t perf_session__data_offset(const struct evlist *evlist)
+{
+ struct evsel *evsel;
+ size_t data_offset;
+
+ data_offset = sizeof(struct perf_file_header);
+ evlist__for_each_entry(evlist, evsel) {
+ data_offset += evsel->core.ids * sizeof(u64);
+ }
+ data_offset += evlist->core.nr_entries * sizeof(struct perf_file_attr);
+
+ return data_offset;
+}
+
int perf_session__inject_header(struct perf_session *session,
struct evlist *evlist,
int fd,
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 08563c1f1bff..56916dabce7b 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -136,6 +136,8 @@ int perf_session__inject_header(struct perf_session *session,
int fd,
struct feat_copier *fc);
+size_t perf_session__data_offset(const struct evlist *evlist);
+
void perf_header__set_feat(struct perf_header *header, int feat);
void perf_header__clear_feat(struct perf_header *header, int feat);
bool perf_header__has_feat(const struct perf_header *header, int feat);
--
2.37.0.rc0.104.g0611611a94-goog
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