diff --git a/sys/cddl/compat/opensolaris/sys/lock.h b/sys/cddl/compat/opensolaris/sys/lock.h
new file mode 100644
index 000000000000..51fcd6789684
--- /dev/null
+++ b/sys/cddl/compat/opensolaris/sys/lock.h
@@ -0,0 +1,46 @@
+/*-
+ * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * 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 AUTHORS 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 AUTHORS 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _OPENSOLARIS_SYS_LOCK_H_
+#define	_OPENSOLARIS_SYS_LOCK_H_
+
+#include_next <sys/lock.h>
+
+#ifdef _KERNEL
+
+#define	LO_ALLMASK	(LO_INITIALIZED | LO_WITNESS | LO_QUIET |	\
+			 LO_RECURSABLE | LO_SLEEPABLE | LO_UPGRADABLE |	\
+			 LO_DUPOK | LO_ENROLLPEND | LO_CLASSMASK |	\
+			 LO_NOPROFILE)
+#define	LO_EXPECTED	(LO_INITIALIZED | LO_WITNESS | LO_RECURSABLE |	\
+			 LO_SLEEPABLE | LO_UPGRADABLE | LO_DUPOK |	\
+			 /* sx lock class */(2 << LO_CLASSSHIFT))
+
+#endif	/* defined(_KERNEL) */
+
+#endif	/* _OPENSOLARIS_SYS_LOCK_H_ */
diff --git a/sys/cddl/compat/opensolaris/sys/mutex.h b/sys/cddl/compat/opensolaris/sys/mutex.h
index 14e69c4605d9..dac724953c2a 100644
--- a/sys/cddl/compat/opensolaris/sys/mutex.h
+++ b/sys/cddl/compat/opensolaris/sys/mutex.h
@@ -48,6 +48,9 @@ typedef struct sx	kmutex_t;
 
 #define	mutex_init(lock, desc, type, arg)	do {			\
 	ASSERT((type) == MUTEX_DEFAULT);				\
+	KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) !=		\
+	    LO_EXPECTED, ("lock %s already initialized", #lock));	\
+	bzero((lock), sizeof(struct sx));				\
 	sx_init_flags((lock), "zfs:" #lock, SX_DUPOK);			\
 } while (0)
 #define	mutex_destroy(lock)	sx_destroy(lock)
diff --git a/sys/cddl/compat/opensolaris/sys/rwlock.h b/sys/cddl/compat/opensolaris/sys/rwlock.h
index 638ca8449cfe..6facd7a7b5eb 100644
--- a/sys/cddl/compat/opensolaris/sys/rwlock.h
+++ b/sys/cddl/compat/opensolaris/sys/rwlock.h
@@ -53,8 +53,12 @@ typedef	struct sx	krwlock_t;
 #define	RW_LOCK_HELD(x)		(rw_lock_held((x)))
 #define	RW_ISWRITER(x)		(rw_iswriter(x))
 
-#define	rw_init(lock, desc, type, arg)					\
-	sx_init_flags((lock), "zfs:" #lock, SX_DUPOK)
+#define	rw_init(lock, desc, type, arg)	do {				\
+	KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) !=		\
+	    LO_EXPECTED, ("lock %s already initialized", #lock));	\
+	bzero((lock), sizeof(struct sx));				\
+	sx_init_flags((lock), "zfs:" #lock, SX_DUPOK);			\
+} while (0)
 #define	rw_destroy(lock)	sx_destroy(lock)
 #define	rw_enter(lock, how)	do {					\
 	if ((how) == RW_READER)						\
diff --git a/sys/compat/opensolaris/sys/lock.h b/sys/compat/opensolaris/sys/lock.h
new file mode 100644
index 000000000000..51fcd6789684
--- /dev/null
+++ b/sys/compat/opensolaris/sys/lock.h
@@ -0,0 +1,46 @@
+/*-
+ * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * 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 AUTHORS 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 AUTHORS 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _OPENSOLARIS_SYS_LOCK_H_
+#define	_OPENSOLARIS_SYS_LOCK_H_
+
+#include_next <sys/lock.h>
+
+#ifdef _KERNEL
+
+#define	LO_ALLMASK	(LO_INITIALIZED | LO_WITNESS | LO_QUIET |	\
+			 LO_RECURSABLE | LO_SLEEPABLE | LO_UPGRADABLE |	\
+			 LO_DUPOK | LO_ENROLLPEND | LO_CLASSMASK |	\
+			 LO_NOPROFILE)
+#define	LO_EXPECTED	(LO_INITIALIZED | LO_WITNESS | LO_RECURSABLE |	\
+			 LO_SLEEPABLE | LO_UPGRADABLE | LO_DUPOK |	\
+			 /* sx lock class */(2 << LO_CLASSSHIFT))
+
+#endif	/* defined(_KERNEL) */
+
+#endif	/* _OPENSOLARIS_SYS_LOCK_H_ */
diff --git a/sys/compat/opensolaris/sys/mutex.h b/sys/compat/opensolaris/sys/mutex.h
index 14e69c4605d9..dac724953c2a 100644
--- a/sys/compat/opensolaris/sys/mutex.h
+++ b/sys/compat/opensolaris/sys/mutex.h
@@ -48,6 +48,9 @@ typedef struct sx	kmutex_t;
 
 #define	mutex_init(lock, desc, type, arg)	do {			\
 	ASSERT((type) == MUTEX_DEFAULT);				\
+	KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) !=		\
+	    LO_EXPECTED, ("lock %s already initialized", #lock));	\
+	bzero((lock), sizeof(struct sx));				\
 	sx_init_flags((lock), "zfs:" #lock, SX_DUPOK);			\
 } while (0)
 #define	mutex_destroy(lock)	sx_destroy(lock)
diff --git a/sys/compat/opensolaris/sys/rwlock.h b/sys/compat/opensolaris/sys/rwlock.h
index 638ca8449cfe..6facd7a7b5eb 100644
--- a/sys/compat/opensolaris/sys/rwlock.h
+++ b/sys/compat/opensolaris/sys/rwlock.h
@@ -53,8 +53,12 @@ typedef	struct sx	krwlock_t;
 #define	RW_LOCK_HELD(x)		(rw_lock_held((x)))
 #define	RW_ISWRITER(x)		(rw_iswriter(x))
 
-#define	rw_init(lock, desc, type, arg)					\
-	sx_init_flags((lock), "zfs:" #lock, SX_DUPOK)
+#define	rw_init(lock, desc, type, arg)	do {				\
+	KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) !=		\
+	    LO_EXPECTED, ("lock %s already initialized", #lock));	\
+	bzero((lock), sizeof(struct sx));				\
+	sx_init_flags((lock), "zfs:" #lock, SX_DUPOK);			\
+} while (0)
 #define	rw_destroy(lock)	sx_destroy(lock)
 #define	rw_enter(lock, how)	do {					\
 	if ((how) == RW_READER)						\