Apply by doing:
	cd /usr/src/sys/miscfs
	patch -p0 < 011_miscfs.patch

And then rebuild your kernel.

Index: fdesc/fdesc_vnops.c
===================================================================
RCS file: /cvs/src/sys/miscfs/fdesc/fdesc_vnops.c,v
retrieving revision 1.13
retrieving revision 1.15
diff -u -r1.13 -r1.15
--- fdesc/fdesc_vnops.c	1999/04/28 09:28:15	1.13
+++ fdesc/fdesc_vnops.c	1999/08/13 07:05:46	1.15
@@ -718,11 +718,11 @@
 
 	if (uio->uio_resid < UIO_MX)
 		return (EINVAL);
-	if (uio->uio_offset < 0)
-		return (EINVAL);
 
 	error = 0;
 	i = uio->uio_offset;
+	if (i < 0)
+		return (EINVAL);
 	bzero((caddr_t)&d, UIO_MX);
 	d.d_reclen = UIO_MX;
 
Index: procfs/procfs_vnops.c
===================================================================
RCS file: /cvs/src/sys/miscfs/procfs/procfs_vnops.c,v
retrieving revision 1.12
retrieving revision 1.14
diff -u -r1.12 -r1.14
--- procfs/procfs_vnops.c	1998/08/06 19:34:46	1.12
+++ procfs/procfs_vnops.c	1999/08/13 07:05:46	1.14
@@ -825,11 +825,11 @@
 
 	if (uio->uio_resid < UIO_MX)
 		return (EINVAL);
-	if (uio->uio_offset < 0)
-		return (EINVAL);
 
 	error = 0;
 	i = uio->uio_offset;
+	if (i < 0)
+		return (EINVAL);
 	bzero((caddr_t)&d, UIO_MX);
 	d.d_reclen = UIO_MX;