Index: bpf.c
===================================================================
RCS file: /cvs/src/sys/net/bpf.c,v
retrieving revision 1.109
diff -u -p -r1.109 bpf.c
--- bpf.c	23 Sep 2014 00:26:11 -0000	1.109
+++ bpf.c	23 Sep 2014 07:35:03 -0000
@@ -85,6 +85,7 @@ int bpf_maxbufsize = BPF_MAXBUFSIZE;
  */
 struct bpf_if	*bpf_iflist;
 LIST_HEAD(, bpf_d) bpf_d_list;
+struct rwlock bpf_d_lock;
 
 void	bpf_allocbufs(struct bpf_d *);
 void	bpf_freed(struct bpf_d *);
@@ -310,6 +311,7 @@ void
 bpfilterattach(int n)
 {
 	LIST_INIT(&bpf_d_list);
+	rw_init(&bpf_d_lock, "bpfd");
 }
 
 /*
@@ -1515,12 +1517,17 @@ bpfdetach(struct ifnet *ifp)
 				 * Locate the minor number and nuke the vnode
 				 * for any open instance.
 				 */
-				LIST_FOREACH(d, &bpf_d_list, bd_list)
-					if (d == bd) {
-						vdevgone(maj, d->bd_unit,
-						    d->bd_unit, VCHR);
+				rw_enter_read(&bpf_d_lock);
+				LIST_FOREACH(d, &bpf_d_list, bd_list) {
+					if (d == bd)
 						break;
-					}
+				}
+				rw_exit_read(&bpf_d_lock);
+
+				if (d != NULL) {
+					vdevgone(maj, d->bd_unit,
+					    d->bd_unit, VCHR);
+				}
 			}
 
 			free(bp, M_DEVBUF, 0);
@@ -1591,10 +1598,14 @@ bpfilter_lookup(int unit)
 {
 	struct bpf_d *bd;
 
-	LIST_FOREACH(bd, &bpf_d_list, bd_list)
+	rw_enter_read(&bpf_d_lock);
+	LIST_FOREACH(bd, &bpf_d_list, bd_list) {
 		if (bd->bd_unit == unit)
-			return (bd);
-	return (NULL);
+			break;
+	}
+	rw_exit_read(&bpf_d_lock);
+
+	return (bd);
 }
 
 struct bpf_d *
@@ -1602,19 +1613,37 @@ bpfilter_create(int unit)
 {
 	struct bpf_d *bd;
 
-	if ((bd = bpfilter_lookup(unit)) != NULL)
-		return (NULL);
-	if ((bd = malloc(sizeof(*bd), M_DEVBUF, M_NOWAIT|M_ZERO)) != NULL) {
-		bd->bd_unit = unit;
-		LIST_INSERT_HEAD(&bpf_d_list, bd, bd_list);
+	rw_enter_write(&bpf_d_lock);
+
+	LIST_FOREACH(bd, &bpf_d_list, bd_list) {
+		if (bd->bd_unit == unit)
+			break;
+	}
+
+	if (bd != NULL) {
+		bd = NULL;
+		goto out;
 	}
+
+	bd = malloc(sizeof(*bd), M_DEVBUF, M_NOWAIT|M_ZERO);
+	if (bd == NULL)
+		goto out;
+
+	bd->bd_unit = unit;
+	LIST_INSERT_HEAD(&bpf_d_list, bd, bd_list);
+
+out:
+	rw_exit_write(&bpf_d_lock);
 	return (bd);
 }
 
 void
 bpfilter_destroy(struct bpf_d *bd)
 {
+	rw_enter_write(&bpf_d_lock);
 	LIST_REMOVE(bd, bd_list);
+	rw_exit_write(&bpf_d_lock);
+
 	free(bd, M_DEVBUF, 0);
 }