// causes it to fail.
	if runtime.GOOS == "dragonfly" {
		size = C.size_t(0x7fffffff << (32 * (^uintptr(0) >> 63)))
	}

	p := C.malloc(size)
	if p == nil {
		fmt.Println("malloc: C.malloc returned nil")
		// Just exit normally--the test script expects this
		// program to crash, so exiting normally indicates failure.
	}

			minSizeForMallocHeaderIsSizeClass = true
			break
		}
	}
	if !minSizeForMallocHeaderIsSizeClass {
		throw("min size of malloc header is not a size class boundary")
	}
	// Check that the pointer bitmap for all small sizes without a malloc header
	// fits in a word.
	if minSizeForMallocHeader/goarch.PtrSize > 8*goarch.PtrSize {
		throw("max pointer/scan bitmap size for headerless objects is too large")

{
	uintptr *pbounds;

	/* The memory sanitizer distributed with versions of clang
	   before 3.8 has a bug: if you call mmap before malloc, mmap
	   may return an address that is later overwritten by the msan
	   library.  Avoid this problem by forcing a call to malloc
	   here, before we ever call malloc.

	   This is only required for the memory sanitizer, so it's
	   unfortunate that we always run it.  It should be possible

	guards).
	free(NULL) has a fast-path special case in TSAN, so it doesn't
	trigger signal delivery.
	free(malloc(0)) would work (triggering the interceptors in malloc), but
	it also runs a bunch of user-supplied malloc hooks.

	So we choose strncpy(_, _, 0): it requires an extra header,
	but it's standard and should be very efficient.

{
	uintptr *pbounds;

	/* The memory sanitizer distributed with versions of clang
	   before 3.8 has a bug: if you call mmap before malloc, mmap
	   may return an address that is later overwritten by the msan
	   library.  Avoid this problem by forcing a call to malloc
	   here, before we ever call malloc.

	   This is only required for the memory sanitizer, so it's
	   unfortunate that we always run it.  It should be possible

	char *stack1 = malloc(STACK_SIZE);
	if (stack1 == NULL) {
		perror("malloc");
		exit(1);
	}

	// Allocate the second stack before freeing the first to ensure we don't get
	// the same address from malloc.
	//
	// Will be freed in stackSwitchThread2.
	stack2 = malloc(STACK_SIZE);
	if (stack1 == NULL) {
		perror("malloc");
		exit(1);
	}

	if (getcontext(&uctx_switch) == -1) {

// 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() {

//go:build unix
// +build unix

package main

// Test that an external C thread that is calling malloc can be hit
// with SIGCHLD signals. This used to fail when built with the race
// detector, because in that case the signal handler would indirectly
// call the C malloc function.

/*
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

// 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 collide with the calls
// made by the os/user package.

// #cgo CFLAGS: -fsanitize=thread
// #cgo LDFLAGS: -fsanitize=thread
// #include <stdlib.h>
import "C"

import (
	"fmt"
	"os"
	"os/user"
	"runtime"

  reflectOffs,
  timer,
  traceStrings,
  userArenaState
# Above MALLOC are things that can allocate memory.
< MALLOC
# Below MALLOC is the malloc implementation.
< fin,
  spanSetSpine,
  mspanSpecial,
  traceTypeTab,
  MPROF;

# We can acquire gcBitsArenas for pinner bits, and
# it's guarded by mspanSpecial.
MALLOC, mspanSpecial < gcBitsArenas;

# Memory profiling