make sure cleanup handler is only called once

test/pthread/tst-too-many-cleanups.c

@@ -0,0 +1,97 @@
+/*
+ * This illustrates the bug where the cleanup function
+ * of a thread may be called too many times.
+ *
+ * main thread:
+ *  - grab mutex
+ *  - spawn thread1
+ *  - go to sleep
+ * thread1:
+ *  - register cleanup handler via pthread_cleanup_push()
+ *  - try to grab mutex and sleep
+ * main:
+ *  - kill thread1
+ *  - go to sleep
+ * thread1 cleanup handler:
+ *  - try to grab mutex and sleep
+ * main:
+ *  - kill thread1
+ *  - go to sleep
+ * thread1 cleanup handler:
+ *  - wrongly called again
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <assert.h>
+#include <unistd.h>
+
+#define warn(fmt, args...) fprintf(stderr, "[%p] " fmt, (void*)pthread_self(), ## args)
+#define warnf(fmt, args...) warn("%s:%i: " fmt, __FUNCTION__, __LINE__, ## args)
+
+int ok_to_kill_thread;
+
+static void thread_killed(void *arg);
+
+static void *KillMeThread(void *thread_par)
+{
+	pthread_t pthread_id;
+
+	warnf("Starting child thread\n");
+
+	pthread_id = pthread_self();
+	pthread_cleanup_push(thread_killed, (void *)pthread_id);
+
+	pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
+	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
+
+	/* main code */
+	warnf("please kill me now\n");
+	while (1)
+		ok_to_kill_thread = 1;
+
+	pthread_cleanup_pop(0);
+}
+
+static void thread_killed(void *arg)
+{
+	static num_times_called = 0;
+
+	warnf("killing %p [cnt=%i]\n", arg, ++num_times_called);
+	assert(num_times_called == 1);
+
+	/* pick any cancellation endpoint, sleep() will do just fine */
+	while (1) {
+		warnf("sleeping in cancellation endpoint ...\n");
+		sleep(1);
+	}
+
+	warnf("done cleaning up\n");
+}
+
+int main(int argc, char *argv[])
+{
+	int count = 3;
+	pthread_t app_pthread_id;
+
+	ok_to_kill_thread = 0;
+
+	pthread_create(&app_pthread_id, NULL, KillMeThread, NULL);
+
+	warnf("waiting for thread to prepare itself\n");
+	while (!ok_to_kill_thread)
+		;
+
+	while (count--) {
+		warnf("killing thread\n");
+		pthread_cancel(app_pthread_id);
+		sleep(3);
+	}
+
+	return 0;
+}