1 files changed, 28 insertions, 0 deletions
diff --git a/src/runtime/race/race_linux_test.go b/src/runtime/race/race_linux_test.go
index e8a2d0fd8c..947ed7ca39 100644
--- a/src/runtime/race/race_linux_test.go
+++ b/src/runtime/race/race_linux_test.go
@@ -35,3 +35,31 @@ func TestAtomicMmap(t *testing.T) {
 		t.Fatalf("bad atomic value: %v, want 2", *a)
 	}
 }
+
+func TestAtomicPageBoundary(t *testing.T) {
+	// Test that atomic access near (but not cross) a page boundary
+	// doesn't fault. See issue 60825.
+
+	// Mmap two pages of memory, and make the second page inaccessible,
+	// so we have an address at the end of a page.
+	pagesize := syscall.Getpagesize()
+	b, err := syscall.Mmap(0, 0, 2*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+	if err != nil {
+		t.Fatalf("mmap failed %s", err)
+	}
+	defer syscall.Munmap(b)
+	err = syscall.Mprotect(b[pagesize:], syscall.PROT_NONE)
+	if err != nil {
+		t.Fatalf("mprotect high failed %s\n", err)
+	}
+
+	// This should not fault.
+	a := (*uint32)(unsafe.Pointer(&b[pagesize-4]))
+	atomic.StoreUint32(a, 1)
+	if x := atomic.LoadUint32(a); x != 1 {
+		t.Fatalf("bad atomic value: %v, want 1", x)
+	}
+	if x := atomic.AddUint32(a, 1); x != 2 {
+		t.Fatalf("bad atomic value: %v, want 2", x)
+	}
+}