diff --git a/src/runtime/mem_bsd.go b/src/runtime/mem_bsd.go
index 13065b61d4..bf2d99678b 100644
--- a/src/runtime/mem_bsd.go
+++ b/src/runtime/mem_bsd.go
@@ -42,7 +42,19 @@ func sysFault(v unsafe.Pointer, n uintptr) {
 }
 
 func sysReserve(v unsafe.Pointer, n uintptr) unsafe.Pointer {
-	p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
+	flags := int32(_MAP_ANON | _MAP_PRIVATE)
+	if raceenabled {
+		// Currently the race detector expects memory to live within a certain
+		// range, and on Darwin 10.10 mmap is prone to ignoring hints, moreso
+		// than later versions and other BSDs (#26475). So, even though it's
+		// potentially dangerous to MAP_FIXED, we do it in the race detection
+		// case because it'll help maintain the race detector's invariants.
+		//
+		// TODO(mknyszek): Drop this once support for Darwin 10.10 is dropped,
+		// and reconsider this when #24133 is addressed.
+		flags |= _MAP_FIXED
+	}
+	p, err := mmap(v, n, _PROT_NONE, flags, -1, 0)
 	if err != 0 {
 		return nil
 	}