runtime: fix race atomic operations on external memory

The assembly is broken: it does `MOVQ g(R12), R14` expecting that
R12 contains tls address, but it does not do get_tls(R12) before.
This magically works on linux: `MOVQ g(R12), R14` is compiled to
`mov %fs:0xfffffffffffffff8,%r14` which does not use R12.
But it crashes on windows.

Add explicit `get_tls(R12)`.

Fixes #16206

Change-Id: Ic1f21a6fef2473bcf9147de6646929781c9c1e98
Reviewed-on: https://go-review.googlesource.com/24590
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/runtime/race/race_linux_test.go b/src/runtime/race/race_linux_test.go
new file mode 100644 (file)
index 0000000..c00ce4d
--- /dev/null
+++ b/src/runtime/race/race_linux_test.go
@@ -0,0 +1,37 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux,race
+
+package race_test
+
+import (
+       "sync/atomic"
+       "syscall"
+       "testing"
+       "unsafe"
+)
+
+func TestAtomicMmap(t *testing.T) {
+       // Test that atomic operations work on "external" memory. Previously they crashed (#16206).
+       // Also do a sanity correctness check: under race detector atomic operations
+       // are implemented inside of race runtime.
+       mem, err := syscall.Mmap(-1, 0, 1<<20, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
+       if err != nil {
+               t.Fatalf("mmap failed: %v", err)
+       }
+       defer syscall.Munmap(mem)
+       a := (*uint64)(unsafe.Pointer(&mem[0]))
+       if *a != 0 {
+               t.Fatalf("bad atomic value: %v, want 0", *a)
+       }
+       atomic.AddUint64(a, 1)
+       if *a != 1 {
+               t.Fatalf("bad atomic value: %v, want 1", *a)
+       }
+       atomic.AddUint64(a, 1)
+       if *a != 2 {
+               t.Fatalf("bad atomic value: %v, want 2", *a)
+       }
+}

diff --git a/src/runtime/race/race_windows_test.go b/src/runtime/race/race_windows_test.go
new file mode 100644 (file)
index 0000000..307a1ea
--- /dev/null
+++ b/src/runtime/race/race_windows_test.go
@@ -0,0 +1,46 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build windows,race
+
+package race_test
+
+import (
+       "sync/atomic"
+       "syscall"
+       "testing"
+       "unsafe"
+)
+
+func TestAtomicMmap(t *testing.T) {
+       // Test that atomic operations work on "external" memory. Previously they crashed (#16206).
+       // Also do a sanity correctness check: under race detector atomic operations
+       // are implemented inside of race runtime.
+       kernel32 := syscall.NewLazyDLL("kernel32.dll")
+       VirtualAlloc := kernel32.NewProc("VirtualAlloc")
+       VirtualFree := kernel32.NewProc("VirtualFree")
+       const (
+               MEM_COMMIT     = 0x00001000
+               MEM_RESERVE    = 0x00002000
+               MEM_RELEASE    = 0x8000
+               PAGE_READWRITE = 0x04
+       )
+       mem, _, err := syscall.Syscall6(VirtualAlloc.Addr(), 4, 0, 1<<20, MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE, 0, 0)
+       if err != 0 {
+               t.Fatalf("VirtualAlloc failed: %v", err)
+       }
+       defer syscall.Syscall(VirtualFree.Addr(), 3, mem, 1<<20, MEM_RELEASE)
+       a := (*uint64)(unsafe.Pointer(mem))
+       if *a != 0 {
+               t.Fatalf("bad atomic value: %v, want 0", *a)
+       }
+       atomic.AddUint64(a, 1)
+       if *a != 1 {
+               t.Fatalf("bad atomic value: %v, want 1", *a)
+       }
+       atomic.AddUint64(a, 1)
+       if *a != 2 {
+               t.Fatalf("bad atomic value: %v, want 2", *a)
+       }
+}

diff --git a/src/runtime/race_amd64.s b/src/runtime/race_amd64.s
index 94ca76da27daf6e1b2bfdbcb2c4e54a86f257240..cc1d92f43709c783ff27c5b745e242ab994f48fe 100644 (file)
--- a/src/runtime/race_amd64.s
+++ b/src/runtime/race_amd64.s
@@ -338,6 +338,7 @@ racecallatomic_ignore:
        // An attempt to synchronize on the address would cause crash.
        MOVQ    AX, R15 // remember the original function
        MOVQ    $__tsan_go_ignore_sync_begin(SB), AX
+       get_tls(R12)
        MOVQ    g(R12), R14
        MOVQ    g_racectx(R14), RARG0   // goroutine context
        CALL    racecall<>(SB)