perf tools: Fixup mmap event consumption
The tail position of the event buffer should only be modified after
actually use that event.
If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.
Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 0df298a..5a11f13 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -810,7 +810,7 @@
ret = perf_evlist__parse_sample(top->evlist, event, &sample);
if (ret) {
pr_err("Can't parse sample, err = %d\n", ret);
- continue;
+ goto next_event;
}
evsel = perf_evlist__id2evsel(session->evlist, sample.id);
@@ -825,13 +825,13 @@
case PERF_RECORD_MISC_USER:
++top->us_samples;
if (top->hide_user_symbols)
- continue;
+ goto next_event;
machine = &session->machines.host;
break;
case PERF_RECORD_MISC_KERNEL:
++top->kernel_samples;
if (top->hide_kernel_symbols)
- continue;
+ goto next_event;
machine = &session->machines.host;
break;
case PERF_RECORD_MISC_GUEST_KERNEL:
@@ -847,7 +847,7 @@
*/
/* Fall thru */
default:
- continue;
+ goto next_event;
}
@@ -859,6 +859,8 @@
machine__process_event(machine, event);
} else
++session->stats.nr_unknown_events;
+next_event:
+ perf_evlist__mmap_consume(top->evlist, idx);
}
}