diff --git a/sys/kern/subr_log.c b/sys/kern/subr_log.c
index 558898265448..71293101f86f 100644
--- a/sys/kern/subr_log.c
+++ b/sys/kern/subr_log.c
@@ -127,9 +127,7 @@ static	int
 logread(dev_t dev, struct uio *uio, int flag)
 {
 	struct msgbuf *mbp = msgbufp;
-	long l;
-	int s;
-	int error = 0;
+	int error = 0, l, s;
 
 	s = splhigh();
 	while (mbp->msg_bufr == mbp->msg_bufx) {
@@ -147,14 +145,14 @@ logread(dev_t dev, struct uio *uio, int flag)
 	logsoftc.sc_state &= ~LOG_RDWAIT;
 
 	while (uio->uio_resid > 0) {
-		l = (long)mbp->msg_bufx - mbp->msg_bufr;
+		l = mbp->msg_bufx - mbp->msg_bufr;
 		if (l < 0)
 			l = mbp->msg_size - mbp->msg_bufr;
-		l = min(l, uio->uio_resid);
+		l = imin(l, uio->uio_resid);
 		if (l == 0)
 			break;
 		error = uiomove((caddr_t)msgbufp->msg_ptr + mbp->msg_bufr,
-		    (int)l, uio);
+		    l, uio);
 		if (error)
 			break;
 		mbp->msg_bufr += l;
@@ -210,15 +208,14 @@ logtimeout(void *arg)
 static	int
 logioctl(dev_t dev, u_long com, caddr_t data, int flag, struct thread *td)
 {
-	long l;
-	int s;
+	int l, s;
 
 	switch (com) {
 
 	/* return number of characters immediately available */
 	case FIONREAD:
 		s = splhigh();
-		l = (long)msgbufp->msg_bufx - msgbufp->msg_bufr;
+		l = msgbufp->msg_bufx - msgbufp->msg_bufr;
 		splx(s);
 		if (l < 0)
 			l += msgbufp->msg_size;
diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index b7a818b1985f..e8cef1b164d9 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -820,7 +820,7 @@ msgbufcopy(struct msgbuf *oldp)
 }
 
 void
-msgbufinit(void *ptr, size_t size)
+msgbufinit(void *ptr, int size)
 {
 	char *cp;
 	static struct msgbuf *oldp = NULL;
@@ -829,7 +829,8 @@ msgbufinit(void *ptr, size_t size)
 	cp = (char *)ptr;
 	msgbufp = (struct msgbuf *) (cp + size);
 	if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
-	    msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
+	    msgbufp->msg_bufx >= size || msgbufp->msg_bufx < 0 ||
+	    msgbufp->msg_bufr >= size || msgbufp->msg_bufr < 0) {
 		bzero(cp, size);
 		bzero(msgbufp, sizeof(*msgbufp));
 		msgbufp->msg_magic = MSG_MAGIC;
diff --git a/sys/sys/msgbuf.h b/sys/sys/msgbuf.h
index 7ac13bfb501d..e6f6da22806a 100644
--- a/sys/sys/msgbuf.h
+++ b/sys/sys/msgbuf.h
@@ -39,17 +39,17 @@
 
 struct msgbuf {
 #define	MSG_MAGIC	0x063062
-	unsigned int	msg_magic;
-	unsigned int	msg_size;		/* size of buffer area */
-	unsigned int	msg_bufx;		/* write pointer */
-	unsigned int	msg_bufr;		/* read pointer */
-	char * 		msg_ptr;		/* pointer to buffer */
+	u_int	msg_magic;
+	int	msg_size;		/* size of buffer area */
+	int	msg_bufx;		/* write pointer */
+	int	msg_bufr;		/* read pointer */
+	char	*msg_ptr;		/* pointer to buffer */
 };
 
 #ifdef _KERNEL
 extern int	msgbuftrigger;
 extern struct	msgbuf *msgbufp;
-void	msgbufinit(void *ptr, size_t size);
+void	msgbufinit(void *ptr, int size);
 
 #if !defined(MSGBUF_SIZE)
 #define	MSGBUF_SIZE	32768