perf: Fix strncpy() use, always make sure it's NUL terminated

For NUL terminated string, always make sure that there's '\0' at the end.

In our case we need a return value, so still use strncpy() and
fix up the tail explicitly.

(strlcpy() returns the size, not the pointer)

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: a.p.zijlstra@chello.nl <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org <paulus@samba.org>
Cc: acme@ghostprotocols.net <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/51623E0B.7070101@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 59412d0..7f0d67e 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4737,7 +4737,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
        } else {
                if (arch_vma_name(mmap_event->vma)) {
                        name = strncpy(tmp, arch_vma_name(mmap_event->vma),
-                                      sizeof(tmp));
+                                      sizeof(tmp) - 1);
+                       tmp[sizeof(tmp) - 1] = '\0';
                        goto got_name;
                }