1 // Copyright 2016 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build linux,race 6 7 package race_test 8 9 import ( 10 "sync/atomic" 11 "syscall" 12 "testing" 13 "unsafe" 14 ) 15 16 func TestAtomicMmap(t *testing.T) { 17 // Test that atomic operations work on "external" memory. Previously they crashed (#16206). 18 // Also do a sanity correctness check: under race detector atomic operations 19 // are implemented inside of race runtime. 20 mem, err := syscall.Mmap(-1, 0, 1<<20, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE) 21 if err != nil { 22 t.Fatalf("mmap failed: %v", err) 23 } 24 defer syscall.Munmap(mem) 25 a := (*uint64)(unsafe.Pointer(&mem[0])) 26 if *a != 0 { 27 t.Fatalf("bad atomic value: %v, want 0", *a) 28 } 29 atomic.AddUint64(a, 1) 30 if *a != 1 { 31 t.Fatalf("bad atomic value: %v, want 1", *a) 32 } 33 atomic.AddUint64(a, 1) 34 if *a != 2 { 35 t.Fatalf("bad atomic value: %v, want 2", *a) 36 } 37 } 38
