diff --git a/include/linux/time64.h b/include/linux/time64.h
index e58f59674ad6dbac2b0a26b4323d3e5098726aba..681c2e34034a8ecec2184ebb5aeb10a1a58f0553 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -39,7 +39,9 @@ struct itimerspec64 {
 /* Located here for timespec[64]_valid_strict */
 #define TIME64_MAX			((s64)~((u64)1 << 63))
 #define KTIME_MAX			((s64)~((u64)1 << 63))
+#define KTIME_MIN			(-KTIME_MAX - 1)
 #define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
+#define KTIME_SEC_MIN			(KTIME_MIN / NSEC_PER_SEC)
 
 /*
  * Limits for settimeofday():
@@ -140,10 +142,13 @@ static inline bool timespec64_valid_settod(const struct timespec64 *ts)
  */
 static inline s64 timespec64_to_ns(const struct timespec64 *ts)
 {
-	/* Prevent multiplication overflow */
-	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
+	/* Prevent multiplication overflow / underflow */
+	if (ts->tv_sec >= KTIME_SEC_MAX)
 		return KTIME_MAX;
 
+	if (ts->tv_sec <= KTIME_SEC_MIN)
+		return KTIME_MIN;
+
 	return ((s64) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
 }