Fix #7087 (integer overflow in getDelayTarget())

includes/Rts.h

@@ -156,6 +156,8 @@ void _assertFail(const char *filename, unsigned int linenum)
 #define TIME_RESOLUTION 1000000000
 typedef StgInt64 Time;
 
+#define TIME_MAX HS_INT64_MAX
+
 #if TIME_RESOLUTION == 1000000000
 // I'm being lazy, but it's awkward to define fully general versions of these
 #define TimeToUS(t)      ((t) / 1000)

rts/posix/Select.c

@@ -67,9 +67,18 @@ static LowResTime getLowResTimeOfDay(void)
  */
 LowResTime getDelayTarget (HsInt us)
 {
-    // round up the target time, because we never want to sleep *less*
-    // than the desired amount.
-    return TimeToLowResTimeRoundUp(getProcessElapsedTime() + USToTime(us));
+    Time elapsed;
+    elapsed = getProcessElapsedTime();
+
+    // If the desired target would be larger than the maximum Time,
+    // default to the maximum Time. (#7087)
+    if (us > TimeToUS(TIME_MAX - elapsed)) {
+        return TimeToLowResTimeRoundDown(TIME_MAX);
+    } else {
+        // round up the target time, because we never want to sleep *less*
+        // than the desired amount.
+        return TimeToLowResTimeRoundUp(elapsed + USToTime(us));
+    }
 }
 
 /* There's a clever trick here to avoid problems when the time wraps