zdtm: Make thread-bomb be bomb

In current implementation of thread bomb effectively only one
thread runs, the rest sit in the read from pipe.

Fix this by making threads constantly creating new ones and
just exiting.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>

test/zdtm.py

@@ -265,7 +265,7 @@ class zdtm_test:
 
 		print "Start test"
 
-		env['ZDTM_THREAD_BOMB'] = "100"
+		env['ZDTM_THREAD_BOMB'] = "5"
 		if not test_flag(self.__desc, 'suid'):
 			env['ZDTM_UID'] = "18943"
 			env['ZDTM_GID'] = "58467"

test/zdtm/live/transition/thread-bomb.c

@@ -8,61 +8,46 @@
 
 #include "zdtmtst.h"
 
-static int p[2];
-static char *buf;
-static int buf_size = 1024;
-
 #define exit_group(code)	\
 	syscall(__NR_exit_group, code)
 
 static void *thread_fn(void *arg)
 {
-	pthread_t t;
-	char c = 0;
-	int ret;
+	pthread_t t, p, *self;
 
-	while (test_go()) {
-		ret = read(p[0], &c, 1);
-		if (ret == -1 && errno == EAGAIN)
-			return NULL;
-		if (ret != 1)
-			goto err;
-		if (pthread_create(&t, NULL, thread_fn, NULL))
-			goto err;
-		pthread_join(t, NULL);
-		if (write(p[1], &c, 1) != 1)
-			goto err;
+	if (arg) {
+		p = *(pthread_t *)arg;
+		pthread_join(p, NULL);
+		free(arg);
 	}
 
-	return NULL;
-err:
-	exit_group(1);
+	self = malloc(sizeof(*self));
+	*self = pthread_self();
+
+	pthread_create(&t, NULL, thread_fn, self);
 	return NULL;
 }
 
 int main(int argc, char **argv)
 {
 	char *val;
+	int max_nr = 1024, i;
 
 	val = getenv("ZDTM_THREAD_BOMB");
 	if (val)
-		buf_size = atoi(val);
-	test_msg("%d\n", buf_size);
-	buf = malloc(buf_size);
-	if (!buf)
-		return 1;
-
-	if (pipe(p))
-		return 1;
-	fcntl(p[0], F_SETFL, O_NONBLOCK);
+		max_nr = atoi(val);
 
-	if (write(p[1], buf, buf_size) != buf_size)
-		return 1;
+	test_msg("%d\n", max_nr);
 
 	test_init(argc, argv);
-	test_daemon();
 
-	thread_fn(NULL);
+	for (i = 0; i < max_nr; i++) {
+		pthread_t p;
+		pthread_create(&p, NULL, thread_fn, NULL);
+	}
+
+	test_daemon();
+	test_waitsig();
 
 	pass();