perf inject: Adjust 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@google.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Colin Ian King <colin.king@intel.com>
Cc: Dave Marchevsky <davemarchevsky@fb.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220621152725.2668041-1-rsilvera@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 063f74f5b8db592890b3cb816bc3a199cf240cbf..54d4e508a09207af5ab6dff3c91bd637c6928342 100644 (file)
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -918,7 +918,7 @@ 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 53332da100e83b9b78b4c8682f264b93d0558b95..6ad629db63b7d00d2afe553f82c8678e7995f0ba 100644 (file)
--- 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 08563c1f1bffe491e23c350ad8163849186fb042..56916dabce7be6536882ba8d4a237bc869ecf79a 100644 (file)
--- 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);