[PATCH] perf tools: ensure comm properly terminated If threads in a multi-threaded process have names shorter than the main thread the comm for the named threads is not properly terminated.

[David Ahern <dsahern@gmail.com>]

e.g., for the process 'namedthreads' where each thread is named noploop%d
where %d is the thread number:

Before:
    perf script -f comm,tid,ip,sym,dso
    noploop:4ads 21616  400a49 noploop (/tmp/namedthreads)
The 'ads' in the thread comm bleeds over from the process name.

After:
    perf script -f comm,tid,ip,sym,dso
       noploop:4 21616  400a49 noploop (/tmp/namedthreads)

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 tools/perf/util/event.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 2044324..2a6f33c 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -74,6 +74,7 @@ static pid_t perf_event__get_comm_tgid(pid_t pid, char *comm, size_t len)
 			if (size >= len)
 				size = len - 1;
 			memcpy(comm, name, size);
+			comm[size] = '\0';
 
 		} else if (memcmp(bf, "Tgid:", 5) == 0) {
 			char *tgids = bf + 5;
-- 
1.7.5.4