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cc98ffb6dc
I introduced this test in #86537, let's remove some unneeded debugging comments. This PR was initially also moving the test to linux directory but looks like it's already done by 17ab9e64464f989b3fe4a304a450581a618097a0 .
114 lines
2.7 KiB
C++
114 lines
2.7 KiB
C++
// RUN: %clang_tsan %s -lstdc++ -o %t && %run %t 2>&1 | FileCheck %s
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#include "../test.h"
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#include <errno.h>
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#include <linux/futex.h>
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#include <pthread.h>
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#include <signal.h>
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#include <stdio.h>
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#include <sys/syscall.h>
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#include <cassert>
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#include <stdexcept>
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#include <thread>
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#include <sanitizer/linux_syscall_hooks.h>
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int futex(int *uaddr, int futex_op, int val, const struct timespec *timeout,
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int *uaddr2, int val3) {
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__sanitizer_syscall_pre_futex(uaddr, futex_op, val, timeout, uaddr2, val3);
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int result = syscall(SYS_futex, uaddr, futex_op, val, timeout, uaddr2, val3);
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__sanitizer_syscall_post_futex(result, uaddr, futex_op, val, timeout, uaddr2,
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val3);
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return result;
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}
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// Simple mutex implementation using futex.
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class Mutex {
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public:
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Mutex() : value(0) {}
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void lock() {
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int c;
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while ((c = __sync_val_compare_and_swap(&value, 0, 1)) != 0) {
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if (c != 1)
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continue;
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int r = futex(&value, FUTEX_WAIT_PRIVATE, 1, nullptr, nullptr, 0);
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if (r == -1 && errno != EAGAIN) {
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fprintf(stderr, "futex wait error\n");
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abort();
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}
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}
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}
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void unlock() {
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value = 0;
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int r = futex(&value, FUTEX_WAKE_PRIVATE, 1, nullptr, nullptr, 0);
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if (r == -1) {
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fprintf(stderr, "futex wake error\n");
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abort();
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}
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}
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private:
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int value;
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};
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Mutex mutex;
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void *Thread(void *x) {
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// Waiting for the futex.
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mutex.lock();
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// Finished waiting.
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return nullptr;
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}
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static void SigprofHandler(int signal, siginfo_t *info, void *context) {
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// Unlock the futex.
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mutex.unlock();
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}
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void InstallSignalHandler() {
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struct sigaction sa;
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sa.sa_sigaction = SigprofHandler;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_RESTART | SA_SIGINFO;
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if (sigaction(SIGPROF, &sa, 0) != 0) {
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fprintf(stderr, "failed to install signal handler\n");
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abort();
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}
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}
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int main() {
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alarm(60); // Kill the test if it hangs.
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// Install the signal handler
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InstallSignalHandler();
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// Lock the futex at first so the other thread will wait for it.
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mutex.lock();
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// Create the thread to wait for the futex.
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pthread_t thread;
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pthread_create(&thread, NULL, Thread, NULL);
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// Just waiting a bit to make sure the thead is at the FUTEX_WAIT_PRIVATE
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// syscall.
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std::this_thread::sleep_for(std::chrono::milliseconds(100));
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// Send the signal to the other thread, which will send the futex wake
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// syscall.
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int r = pthread_kill(thread, SIGPROF);
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assert(r == 0);
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// Futex should be notified and the thread should be able to continue.
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pthread_join(thread, NULL);
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// Exiting successfully.
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fprintf(stderr, "PASS\n");
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return 0;
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}
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// CHECK-NOT: WARNING: ThreadSanitizer:
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// CHECK: PASS
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