Before using this patch, you'll need to apply kib@'s destroy_dev_sched()
patch which can be found at:

	http://people.freebsd.org/~kib/misc/destroy_dev_sched.6.patch

--- cam/scsi/scsi_target.c.orig	Wed May  2 11:42:46 2007
+++ cam/scsi/scsi_target.c	Wed May  2 11:43:11 2007
@@ -210,7 +210,7 @@ targclose(struct cdev *dev, int flag, in
 	softc = (struct targ_softc *)dev->si_drv1;
 	if ((softc->periph == NULL) ||
 	    (softc->state & TARG_STATE_LUN_ENABLED) == 0) {
-		destroy_dev(dev);
+		destroy_dev_sched(dev);
 		FREE(softc, M_TARG);
 		return (0);
 	}
@@ -229,7 +229,7 @@ targclose(struct cdev *dev, int flag, in
 			cam_periph_invalidate(softc->periph);
 			softc->periph = NULL;
 		}
-		destroy_dev(dev);
+		destroy_dev_sched(dev);
 		FREE(softc, M_TARG);
 	}
 	cam_periph_unlock(periph);
--- netsmb/smb_dev.c.orig	Thu Apr 12 10:27:19 2007
+++ netsmb/smb_dev.c	Mon May  7 22:15:49 2007
@@ -175,7 +175,7 @@ nsmb_dev_close(struct cdev *dev, int fla
 */
 	dev->si_drv1 = NULL;
 	free(sdp, M_NSMBDEV);
-	destroy_dev(dev);
+	destroy_dev_sched(dev);
 	splx(s);
 	return 0;
 }
@@ -349,6 +349,8 @@ nsmb_dev_load(module_t mod, int cmd, voi
 		if (error)
 			break;
 		EVENTHANDLER_DEREGISTER(dev_clone, nsmb_dev_tag);
+		destroy_dev_sched_drain(&nsmb_cdevsw);
+		drain_dev_clone_events();
 		printf("netsmb_dev: unloaded\n");
 		break;
 	    default:
--- dev/snp/snp.c.orig	Sun May  6 09:04:58 2007
+++ dev/snp/snp.c	Mon May  7 22:15:21 2007
@@ -466,7 +466,7 @@ snpclose(struct cdev *dev, int flags, in
 	free(snp->snp_buf, M_SNP);
 	snp->snp_flags &= ~SNOOP_OPEN;
 	dev->si_drv1 = NULL;
-	destroy_dev(dev);
+	destroy_dev_sched(dev);
 
 	return (snp_detach(snp));
 }
@@ -641,6 +641,8 @@ snp_modevent(module_t mod, int type, voi
 			return (EBUSY);
 		EVENTHANDLER_DEREGISTER(dev_clone, eh_tag);
 		clone_cleanup(&snpclones);
+		destroy_dev_sched_drain(&snp_cdevsw);
+		drain_dev_clone_events();
 		ldisc_deregister(snooplinedisc);
 		break;
 	default: