Add a regression test for the kthread(9) interface.

Submitted by:	Giovanni Trematerra
		<giovanni dot trematerra at gmail dot com>

2 files changed, 214 insertions, 0 deletions

diff --git a/tools/regression/kthread/kld/Makefile b/tools/regression/kthread/kld/Makefile
new file mode 100644
index 0000000..df1f763
--- /dev/null
+++ b/tools/regression/kthread/kld/Makefile
@@ -0,0 +1,10 @@
+# $FreeBSD$
+
+.PATH:  ${.CURDIR}
+
+KMOD=	kthrdlk
+NO_MAN=
+SRCS=	kthrdlk.c
+WARNS?=	2
+
+.include <bsd.kmod.mk>
diff --git a/tools/regression/kthread/kld/kthrdlk.c b/tools/regression/kthread/kld/kthrdlk.c
new file mode 100644
index 0000000..6485c11
--- /dev/null
+++ b/tools/regression/kthread/kld/kthrdlk.c
@@ -0,0 +1,204 @@
+/*-
+ * Copyright (c) 2010 Giovanni Trematerra <giovanni.trematerra@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ *	PURPOSE:
+ *
+ *	This kernel module helped to identify a deadlock in kthread
+ *	interface, also pointed out a race in kthread_exit function.
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/kthread.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/systm.h>
+#include <sys/time.h>
+
+#ifdef TESTPAUSE_DEBUG
+#define DPRINTF(x) do {							\
+	printf (x);							\
+} while (0)
+#else
+#define DPRINTF(x)
+#endif
+
+static struct mtx test_global_lock;
+static int global_condvar;
+static int test_thrcnt;
+volatile int QUIT;
+
+static void 
+thr_suspender(void *arg)
+{
+	struct thread *td = (struct thread *) arg;
+	int error;
+
+	for (;;) {
+		if (QUIT == 1)
+			break;
+		error = kthread_suspend(td, 10*hz);
+		if (error != 0 && QUIT == 0) {
+			if (error == EWOULDBLOCK)
+				panic("Ooops: kthread deadlock\n");
+			else 
+				panic("kthread_suspend error: %d\n", error);
+			break;
+		}
+	}
+
+	mtx_lock(&test_global_lock);
+	test_thrcnt--;
+	wakeup(&global_condvar);
+	mtx_unlock(&test_global_lock);
+
+	kthread_exit();
+}
+
+static void 
+thr_resumer(void *arg)
+{
+	struct thread *td = (struct thread *) arg;
+	int error;
+
+	for (;;) {
+		/* must be the last thread to exit */
+		if (QUIT == 1 && test_thrcnt == 1)
+			break;
+		error = kthread_resume(td);
+		if (error != 0)
+			panic("%s: error on kthread_resume. error: %d\n",
+				   	__func__, error);
+	}
+
+	mtx_lock(&test_global_lock);
+	test_thrcnt--;
+	wakeup(&global_condvar);
+	mtx_unlock(&test_global_lock);
+
+	kthread_exit();
+}
+
+static void
+thr_getsuspended(void *arg)
+{
+	for (;;) {
+		if (QUIT == 1)
+			break;
+		kthread_suspend_check();
+	}
+
+	mtx_lock(&test_global_lock);
+	test_thrcnt--;
+	wakeup(&global_condvar);
+	mtx_unlock(&test_global_lock);
+
+	kthread_exit();
+}
+
+static void
+kthrdlk_init(void)
+{
+	struct proc *testproc;
+	struct thread *newthr;
+	int error;
+
+	QUIT = 0;
+	test_thrcnt = 3;
+	mtx_init(&test_global_lock, "kthrdlk_lock", NULL, MTX_DEF);
+	testproc = NULL;
+	error = kproc_kthread_add(thr_getsuspended, NULL, &testproc, &newthr,
+	    0, 0, "kthrdlk", "thr_getsuspended");
+	if (error != 0)
+		panic("cannot start thr_getsuspended error: %d\n", error);
+
+	error = kproc_kthread_add(thr_resumer, newthr, &testproc, NULL, 0, 0, 
+	    "kthrdlk", "thr_resumer");
+	if (error != 0)
+		panic("cannot start thr_resumer error: %d\n", error);
+
+	error = kproc_kthread_add(thr_suspender, newthr, &testproc, NULL, 0, 0, 
+	    "kthrdlk", "thr_suspender");
+	if (error != 0)
+		panic("cannot start thr_suspender error: %d\n", error);
+}
+
+static void
+kthrdlk_done(void)
+{
+	int ret;
+	DPRINTF(("sending QUIT signal to the thrdlk threads\n"));
+
+	/* wait kernel threads end */
+	mtx_lock(&test_global_lock);
+	QUIT = 1;
+	while (test_thrcnt != 0) {
+		ret = mtx_sleep(&global_condvar, &test_global_lock, 0, "waiting thrs end", 30 * hz);
+		if (ret == EWOULDBLOCK) {
+			panic("some threads not die! remaing: %d", test_thrcnt);
+			break;
+		}
+	}
+	if (test_thrcnt == 0)
+		DPRINTF(("All test_pause threads die\n"));
+
+	mtx_destroy(&test_global_lock);
+}
+
+static int 
+kthrdlk_handler(module_t mod, int /*modeventtype_t*/ what,
+                            void *arg)
+{
+	switch (what) {
+		case MOD_LOAD:
+			kthrdlk_init();
+			uprintf("kthrdlk loaded!\n");
+			return (0);
+		case MOD_UNLOAD:
+			kthrdlk_done();
+			uprintf("Bye Bye! kthrdlk unloaded!\n");
+			return (0);
+	}
+
+	return (EOPNOTSUPP);
+}
+
+static moduledata_t mod_data= {
+             "kthrdlk",
+             kthrdlk_handler,
+             0
+     };
+
+MODULE_VERSION(kthrdlk, 1);
+
+DECLARE_MODULE(kthrdlk, mod_data, SI_SUB_EXEC, SI_ORDER_ANY);
+