diff --git a/lib/timeutil.c b/lib/timeutil.c
index 12d5fbe0..0ee5004e 100644
--- a/lib/timeutil.c
+++ b/lib/timeutil.c
@@ -222,10 +222,10 @@ convert_timespec(clockid_t from_id, clockid_t to_id,
 uint64_t
 timespec_to_ms(const struct timespec *tv)
 {
-        if (UINT64_MAX / 1000 < tv->tv_sec) {
+        if (UINT64_MAX / 1000 < (uint64_t)tv->tv_sec) {
                 return UINT64_MAX;
         }
-        uint64_t ms1 = tv->tv_sec * 1000;
+        uint64_t ms1 = (uint64_t)tv->tv_sec * 1000;
         uint64_t ms2 = tv->tv_nsec / 1000000;
         if (UINT64_MAX - ms1 < ms2) {
                 return UINT64_MAX;