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// RUN: %clangxx_tsan -O1 %s -o %t && %env_tsan_opts=atexit_sleep_ms=0 %run %t 2>&1 | FileCheck %s
// This test models what happens on Mac when fork
// calls malloc/free inside of our atfork callbacks.
// and ensures that we don't deadlock on malloc/free calls.
#include "../test.h"
#include "syscall.h"
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
// disable_sanitizer_instrumentation on __tsan_test_only_on_fork is not
// transitive, so we must apply it here as well.
// Instrumenting alloc_free_blocks() will result in deadlocks in TSan.
__attribute__((disable_sanitizer_instrumentation)) void alloc_free_blocks() {
// Allocate a bunch of blocks to drain local allocator cache
// and provoke it to lock allocator global mutexes.
const int kBlocks = 1000;
void *blocks[kBlocks];
for (int i = 0; i < kBlocks; i++) {
void *p = malloc(10);
*(volatile char *)p = 0;
blocks[i] = p;
}
for (int i = 0; i < kBlocks; i++)
free(blocks[i]);
}
__attribute__((disable_sanitizer_instrumentation)) extern "C" void
__tsan_test_only_on_fork() {
const char *msg = "__tsan_test_only_on_fork\n";
write(2, msg, strlen(msg));
alloc_free_blocks();
}
static void *background(void *p) {
for (;;)
alloc_free_blocks();
return 0;
}
int main() {
pthread_t th;
pthread_create(&th, 0, background, 0);
pthread_detach(th);
for (int i = 0; i < 10; i++) {
int pid = myfork();
if (pid < 0) {
fprintf(stderr, "failed to fork (%d)\n", errno);
exit(1);
}
if (pid == 0) {
// child
exit(0);
}
// parent
while (wait(0) < 0) {
}
}
fprintf(stderr, "DONE\n");
}
// CHECK: __tsan_test_only_on_fork
// CHECK: DONE
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