perf trace: Handle perf.data files with no tracepoints

Before:

  perf trace -i perf.data
  Segmentation fault (core dumped)
  #

After:

 # perf trace -i perf.data
 Data file does not have raw_syscalls:sys_enter events
 #

When there are no tracepoints in a perf.data file the struct pevent
that contains the list of tracepoints that will be used to lookup the
tracepoint id by name will not be populated, causing a NULL deref.

And we don't need to do all that dance to look at pevents for an entry
with a slighly different name to then lookup the tracepoint by its id on
the evlist, just use the perf_evlist__find_tracepoint_by_name() routine,
that will find the tracepoint, if present.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-egcm21k1e6gcyxpcgjxtmsq3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 7 insertions, 33 deletions

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 476caa129a20..0308d9ee7a77 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1620,52 +1620,26 @@ int __perf_session__set_tracepoints_handlers(struct perf_session *session,
                                              const struct perf_evsel_str_handler *assocs,
                                              size_t nr_assocs)
 {
-        struct perf_evlist *evlist = session->evlist;
-        struct event_format *format;
         struct perf_evsel *evsel;
-        char *tracepoint, *name;
         size_t i;
         int err;
 
         for (i = 0; i < nr_assocs; i++) {
-                err = -ENOMEM;
-                tracepoint = strdup(assocs[i].name);
-                if (tracepoint == NULL)
-                        goto out;
-
-                err = -ENOENT;
-                name = strchr(tracepoint, ':');
-                if (name == NULL)
-                        goto out_free;
-
-                *name++ = '\0';
-                format = pevent_find_event_by_name(session->pevent,
-                                                   tracepoint, name);
-                if (format == NULL) {
-                        /*
-                         * Adding a handler for an event not in the session,
-                         * just ignore it.
-                         */
-                        goto next;
-                }
-
-                evsel = perf_evlist__find_tracepoint_by_id(evlist, format->id);
+                /*
+                 * Adding a handler for an event not in the session,
+                 * just ignore it.
+                 */
+                evsel = perf_evlist__find_tracepoint_by_name(session->evlist, assocs[i].name);
                 if (evsel == NULL)
-                        goto next;
+                        continue;
 
                 err = -EEXIST;
                 if (evsel->handler.func != NULL)
-                        goto out_free;
+                        goto out;
                 evsel->handler.func = assocs[i].handler;
-next:
-                free(tracepoint);
         }
 
         err = 0;
 out:
         return err;
-
-out_free:
-        free(tracepoint);
-        goto out;
 }