diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index 6e04f50e1d..5738a96a87 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -557,6 +557,14 @@ func (h *mheap) sysAlloc(n uintptr) (v unsafe.Pointer, size uintptr) {
 	}
 
 	if size == 0 {
+		if raceenabled {
+			// The race detector assumes the heap lives in
+			// [0x00c000000000, 0x00e000000000), but we
+			// just ran out of hints in this region. Give
+			// a nice failure.
+			throw("too many address space collisions for -race mode")
+		}
+
 		// All of the hints failed, so we'll take any
 		// (sufficiently aligned) address the kernel will give
 		// us.
diff --git a/src/runtime/malloc_test.go b/src/runtime/malloc_test.go
index 854533f238..0bce059f7f 100644
--- a/src/runtime/malloc_test.go
+++ b/src/runtime/malloc_test.go
@@ -7,6 +7,7 @@ package runtime_test
 import (
 	"flag"
 	"fmt"
+	"internal/race"
 	"internal/testenv"
 	"os"
 	"os/exec"
@@ -170,7 +171,17 @@ func TestArenaCollision(t *testing.T) {
 	if os.Getenv("TEST_ARENA_COLLISION") != "1" {
 		cmd := testenv.CleanCmdEnv(exec.Command(os.Args[0], "-test.run=TestArenaCollision", "-test.v"))
 		cmd.Env = append(cmd.Env, "TEST_ARENA_COLLISION=1")
-		if out, err := cmd.CombinedOutput(); !strings.Contains(string(out), "PASS\n") || err != nil {
+		out, err := cmd.CombinedOutput()
+		if race.Enabled {
+			// This test runs the runtime out of hint
+			// addresses, so it will start mapping the
+			// heap wherever it can. The race detector
+			// doesn't support this, so look for the
+			// expected failure.
+			if want := "too many address space collisions"; !strings.Contains(string(out), want) {
+				t.Fatalf("want %q, got:\n%s", want, string(out))
+			}
+		} else if !strings.Contains(string(out), "PASS\n") || err != nil {
 			t.Fatalf("%s\n(exit status %v)", string(out), err)
 		}
 		return