perf offcpu: Accept allowed sample types only

As offcpu-time event is synthesized at the end, it could not get the
all the sample info.  Define OFFCPU_SAMPLE_TYPES for allowed ones and
mask out others in evsel__config() to prevent parse errors.

Because perf sample parsing assumes a specific ordering with the
sample types, setting unsupported one would make it fail to read
data like perf record -d/--data.

Fixes: edc41a1099c2d08c ("perf record: Enable off-cpu analysis with BPF")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220624231313.367909-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c
index b73e84a..f289b77 100644 (file)
--- a/tools/perf/util/bpf_off_cpu.c
+++ b/tools/perf/util/bpf_off_cpu.c
@@ -265,6 +265,12 @@ int off_cpu_write(struct perf_session *session)
 
        sample_type = evsel->core.attr.sample_type;
 
+       if (sample_type & ~OFFCPU_SAMPLE_TYPES) {
+               pr_err("not supported sample type: %llx\n",
+                      (unsigned long long)sample_type);
+               return -1;
+       }
+
        if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) {
                if (evsel->core.id)
                        sid = evsel->core.id[0];
@@ -319,7 +325,6 @@ int off_cpu_write(struct perf_session *session)
                }
                if (sample_type & PERF_SAMPLE_CGROUP)
                        data.array[n++] = key.cgroup_id;
-               /* TODO: handle more sample types */
 
                size = n * sizeof(u64);
                data.hdr.size = size;

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ce499c5..094b0a9 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -48,6 +48,7 @@
 #include "util.h"
 #include "hashmap.h"
 #include "pmu-hybrid.h"
+#include "off_cpu.h"
 #include "../perf-sys.h"
 #include "util/parse-branch-options.h"
 #include <internal/xyarray.h>
@@ -1102,6 +1103,11 @@ static void evsel__set_default_freq_period(struct record_opts *opts,
        }
 }
 
+static bool evsel__is_offcpu_event(struct evsel *evsel)
+{
+       return evsel__is_bpf_output(evsel) && !strcmp(evsel->name, OFFCPU_EVENT);
+}
+
 /*
  * The enable_on_exec/disabled value strategy:
  *
@@ -1366,6 +1372,9 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
         */
        if (evsel__is_dummy_event(evsel))
                evsel__reset_sample_bit(evsel, BRANCH_STACK);
+
+       if (evsel__is_offcpu_event(evsel))
+               evsel->core.attr.sample_type &= OFFCPU_SAMPLE_TYPES;
 }
 
 int evsel__set_filter(struct evsel *evsel, const char *filter)

diff --git a/tools/perf/util/off_cpu.h b/tools/perf/util/off_cpu.h
index 548008f..2dd67c6 100644 (file)
--- a/tools/perf/util/off_cpu.h
+++ b/tools/perf/util/off_cpu.h
@@ -1,6 +1,8 @@
 #ifndef PERF_UTIL_OFF_CPU_H
 #define PERF_UTIL_OFF_CPU_H
 
+#include <linux/perf_event.h>
+
 struct evlist;
 struct target;
 struct perf_session;
@@ -8,6 +10,13 @@ struct record_opts;
 
 #define OFFCPU_EVENT  "offcpu-time"
 
+#define OFFCPU_SAMPLE_TYPES  (PERF_SAMPLE_IDENTIFIER | PERF_SAMPLE_IP | \
+                             PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \
+                             PERF_SAMPLE_ID | PERF_SAMPLE_CPU | \
+                             PERF_SAMPLE_PERIOD | PERF_SAMPLE_CALLCHAIN | \
+                             PERF_SAMPLE_CGROUP)
+
+
 #ifdef HAVE_BPF_SKEL
 int off_cpu_prepare(struct evlist *evlist, struct target *target,
                    struct record_opts *opts);