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go/misc/cgo/testsanitizers/tsan4.go
Ian Lance Taylor a5d1a72a40 cmd/cgo, runtime, runtime/cgo: TSAN support for malloc
Acquire and release the TSAN synchronization point when calling malloc,
just as we do when calling any other C function. If we don't do this,
TSAN will report false positive errors about races calling malloc and
free.

We used to have a special code path for malloc and free, going through
the runtime functions cmalloc and cfree. The special code path for cfree
was no longer used even before this CL. This CL stops using the special
code path for malloc, because there is no place along that path where we
could conditionally insert the TSAN synchronization. This CL removes
the support for the special code path for both functions.

Instead, cgo now automatically generates the malloc function as though
it were referenced as C.malloc.  We need to automatically generate it
even if C.malloc is not called, even if malloc and size_t are not
declared, to support cgo-provided functions like C.CString.

Change-Id: I829854ec0787a80f33fa0a8a0dc2ee1d617830e2
Reviewed-on: https://go-review.googlesource.com/23260
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2016-05-25 23:22:24 +00:00

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634 B
Go

// 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.
package main
// Check that calls to C.malloc/C.free do not trigger TSAN false
// positive reports.
// #cgo CFLAGS: -fsanitize=thread
// #cgo LDFLAGS: -fsanitize=thread
// #include <stdlib.h>
import "C"
import (
"runtime"
"sync"
)
func main() {
var wg sync.WaitGroup
for i := 0; i < 10; i++ {
wg.Add(1)
go func() {
defer wg.Done()
for i := 0; i < 100; i++ {
p := C.malloc(C.size_t(i * 10))
runtime.Gosched()
C.free(p)
}
}()
}
wg.Wait()
}