Don't try to "validate" a non-existing timeval.

settime() with a NULL timeval is silly but legal.

Noticed by Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/time.c

@@ -155,7 +155,7 @@ int do_sys_settimeofday(struct timespec *tv, struct timezone *tz)
 	static int firsttime = 1;
 	int error = 0;
 
-	if (!timespec_valid(tv))
+	if (tv && !timespec_valid(tv))
 		return -EINVAL;
 
 	error = security_settime(tv, tz);

security/seclvl.c

@@ -368,8 +368,8 @@ static int seclvl_capable(struct task_struct *tsk, int cap)
  */
 static int seclvl_settime(struct timespec *tv, struct timezone *tz)
 {
+	if (tv && seclvl > 1) {
 		struct timespec now;
-	if (seclvl > 1) {
 		now = current_kernel_time();
 		if (tv->tv_sec < now.tv_sec ||
 		    (tv->tv_sec == now.tv_sec && tv->tv_nsec < now.tv_nsec)) {