2 files changed, 93 insertions, 0 deletions
diff --git a/tools/test/callout_free/Makefile b/tools/test/callout_free/Makefile
new file mode 100644
index 000000000000..ee17d752b820
--- /dev/null
+++ b/tools/test/callout_free/Makefile
@@ -0,0 +1,6 @@
+# $FreeBSD$
+
+KMOD=	callout_free
+SRCS=	callout_free.c
+
+.include <bsd.kmod.mk>
diff --git a/tools/test/callout_free/callout_free.c b/tools/test/callout_free/callout_free.c
new file mode 100644
index 000000000000..4556687e06f6
--- /dev/null
+++ b/tools/test/callout_free/callout_free.c
@@ -0,0 +1,87 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Eric van Gyzen
+ *
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Free a pending callout.  This was useful for testing the
+ * "show callout_last" ddb command.
+ */
+
+#include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/systm.h>
+
+static struct callout callout_free;
+static struct mtx callout_free_mutex;
+static int callout_free_arg;
+
+static void
+callout_free_func(void *arg)
+{
+	printf("squirrel!\n");
+	mtx_destroy(&callout_free_mutex);
+	memset(&callout_free, 'C', sizeof(callout_free));
+}
+
+static int
+callout_free_load(module_t mod, int cmd, void *arg)
+{
+	int error;
+
+	switch (cmd) {
+	case MOD_LOAD:
+		mtx_init(&callout_free_mutex, "callout_free", NULL, MTX_DEF);
+		/*
+		 * Do not pass CALLOUT_RETURNUNLOCKED so the callout
+		 * subsystem will unlock the "destroyed" mutex.
+		 */
+		callout_init_mtx(&callout_free, &callout_free_mutex, 0);
+		printf("callout_free_func = %p\n", callout_free_func);
+		printf("callout_free_arg = %p\n", &callout_free_arg);
+		callout_reset(&callout_free, hz/10, callout_free_func,
+		    &callout_free_arg);
+		error = 0;
+		break;
+
+	case MOD_UNLOAD:
+		error = 0;
+		break;
+
+	default:
+		error = EOPNOTSUPP;
+		break;
+	}
+
+	return (error);
+}
+
+DEV_MODULE(callout_free, callout_free_load, NULL);