Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  - Fix a segfault in 'perf probe' when removing uprobe events. (Masami Hiramatsu)

  - Synthesize COMM event for workloads started from the command line in 'perf
    record' so that we can have the pid->comm mapping before we get the real
    PERF_RECORD_COMM switching from perf to the workload. (Namhyung Kim)

  - Fix build tools/vm/ due to removal of tools/lib/api/fs/debugfs.h.
    (Arnaldo Carvalho de Melo)

Infrastructure changes:

  - Fix the make tarball targets by including the recently added err.h header in
    the perf MANIFEST file. (Jiri Olsa)

  - Don't assume that the event parser returns a non empty evlist. (Wang Nan)

  - Add way to disambiguate feature detection state files, needed to use
    tools/build feature detection for multiple components in a single O= output
    dir, which will be the case with tools/perf/ and tools/lib/bpf/.
    (Arnaldo Carvalho de Melo)

  - Fixup FEATURE_{TESTS,DISPLAY} inversion in tools/lib/bpf/. (Arnaldo Carvalho de Melo)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

6 files changed, 42 insertions, 4 deletions

diff --git a/tools/perf/MANIFEST b/tools/perf/MANIFEST
index 2a958a80c763..9e6bdf5b2df6 100644
--- a/tools/perf/MANIFEST
+++ b/tools/perf/MANIFEST
@@ -50,6 +50,7 @@ tools/include/linux/poison.h
 tools/include/linux/rbtree.h
 tools/include/linux/rbtree_augmented.h
 tools/include/linux/types.h
+tools/include/linux/err.h
 include/asm-generic/bitops/arch_hweight.h
 include/asm-generic/bitops/const_hweight.h
 include/asm-generic/bitops/fls64.h
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 94385ee89dc8..f7882ae9ebc6 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -380,8 +380,11 @@ static int perf_del_probe_events(struct strfilter *filter)
 		goto out;
 
 	klist = strlist__new(NULL, NULL);
-	if (!klist)
-		return -ENOMEM;
+	ulist = strlist__new(NULL, NULL);
+	if (!klist || !ulist) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	ret = probe_file__get_events(kfd, filter, klist);
 	if (ret == 0) {
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 142eeb341b29..a01c8ae1ee07 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -636,8 +636,21 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	/*
 	 * Let the child rip
 	 */
-	if (forks)
+	if (forks) {
+		union perf_event event;
+		/*
+		 * Some H/W events are generated before COMM event
+		 * which is emitted during exec(), so perf script
+		 * cannot see a correct process name for those events.
+		 * Synthesize COMM event to prevent it.
+		 */
+		perf_event__synthesize_comm(tool, &event,
+					    rec->evlist->workload.pid,
+					    process_synthesized_event,
+					    machine);
+
 		perf_evlist__start_workload(rec->evlist);
+	}
 
 	if (opts->initial_delay) {
 		usleep(opts->initial_delay * 1000);
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 497157affc9c..6214ad47d554 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -167,7 +167,7 @@ static int perf_event__prepare_comm(union perf_event *event, pid_t pid,
 	return 0;
 }
 
-static pid_t perf_event__synthesize_comm(struct perf_tool *tool,
+pid_t perf_event__synthesize_comm(struct perf_tool *tool,
 					 union perf_event *event, pid_t pid,
 					 perf_event__handler_t process,
 					 struct machine *machine)
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index f729df5e25e6..be5cbc7be889 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -478,6 +478,11 @@ int perf_event__synthesize_sample(union perf_event *event, u64 type,
 				  const struct perf_sample *sample,
 				  bool swapped);
 
+pid_t perf_event__synthesize_comm(struct perf_tool *tool,
+				  union perf_event *event, pid_t pid,
+				  perf_event__handler_t process,
+				  struct machine *machine);
+
 int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 				       union perf_event *event,
 				       pid_t pid, pid_t tgid,
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 0fde5293a38e..61c2bc20926d 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -827,6 +827,11 @@ void parse_events__set_leader(char *name, struct list_head *list)
 {
 	struct perf_evsel *leader;
 
+	if (list_empty(list)) {
+		WARN_ONCE(true, "WARNING: failed to set leader: empty list");
+		return;
+	}
+
 	__perf_evlist__set_leader(list);
 	leader = list_entry(list->next, struct perf_evsel, node);
 	leader->group_name = name ? strdup(name) : NULL;
@@ -1176,6 +1181,11 @@ int parse_events(struct perf_evlist *evlist, const char *str,
 	if (!ret) {
 		struct perf_evsel *last;
 
+		if (list_empty(&data.list)) {
+			WARN_ONCE(true, "WARNING: event parser found nothing");
+			return -1;
+		}
+
 		perf_evlist__splice_list_tail(evlist, &data.list);
 		evlist->nr_groups += data.nr_groups;
 		last = perf_evlist__last(evlist);
@@ -1285,6 +1295,12 @@ foreach_evsel_in_last_glob(struct perf_evlist *evlist,
 	struct perf_evsel *last = NULL;
 	int err;
 
+	/*
+	 * Don't return when list_empty, give func a chance to report
+	 * error when it found last == NULL.
+	 *
+	 * So no need to WARN here, let *func do this.
+	 */
 	if (evlist->nr_entries > 0)
 		last = perf_evlist__last(evlist);