perf tools: Don't use parent comm if not set at fork time
As the parent comm then is worthless, confusing users about the
thread where the sample really happened, leading to think that
the sample happened in the parent, not where it really happened,
in the children of a thread for which a PERF_RECORD_COMM event
was not received.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1266627727-19715-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 634b7f7..9e8995e 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -36,7 +36,10 @@
if (self->comm)
free(self->comm);
self->comm = strdup(comm);
- return self->comm ? 0 : -ENOMEM;
+ if (self->comm == NULL)
+ return -ENOMEM;
+ self->comm_set = true;
+ return 0;
}
int thread__comm_len(struct thread *self)
@@ -255,11 +258,14 @@
{
int i;
- if (self->comm)
- free(self->comm);
- self->comm = strdup(parent->comm);
- if (!self->comm)
- return -ENOMEM;
+ if (parent->comm_set) {
+ if (self->comm)
+ free(self->comm);
+ self->comm = strdup(parent->comm);
+ if (!self->comm)
+ return -ENOMEM;
+ self->comm_set = true;
+ }
for (i = 0; i < MAP__NR_TYPES; ++i)
if (map_groups__clone(&self->mg, &parent->mg, i) < 0)