[PATCH] perf: fix strlen() bug in perf_event__synthesize_event_type()

[Stephane Eranian <eranian@google.com>]

The event_type record has a max length for the event name.
It's called MAX_EVENT_NAME.
    
The name may be truncated to fit the max length. But the
header.size still reflects the original name length. If
that length is > MAX_EVENT_NAME, then the header.size
field is bogus. Fix this by using the length of the name
after the potential truncation.
    
Signed-off-by: Stephane Eranian <eranian@google.com>
---

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 3e7e0b0..ecd7f4d 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2105,7 +2105,7 @@ int perf_event__synthesize_event_type(struct perf_tool *tool,
 	strncpy(ev.event_type.event_type.name, name, MAX_EVENT_NAME - 1);
 
 	ev.event_type.header.type = PERF_RECORD_HEADER_EVENT_TYPE;
-	size = strlen(name);
+	size = strlen(ev.event_type.event_type.name);
 	size = ALIGN(size, sizeof(u64));
 	ev.event_type.header.size = sizeof(ev.event_type) -
 		(sizeof(ev.event_type.event_type.name) - size);