diff --git a/drivers/isdn/hisax/hisax_fcpcipnp.c b/drivers/isdn/hisax/hisax_fcpcipnp.c
index dc7ef95..dbcca28 100644
--- a/drivers/isdn/hisax/hisax_fcpcipnp.c
+++ b/drivers/isdn/hisax/hisax_fcpcipnp.c
@@ -387,8 +387,7 @@
 
 	DBG(0x40, "hdlc_fill_fifo");
 
-	if (skb->len == 0)
-		BUG();
+	BUG_ON(skb->len == 0);
 
 	bcs->ctrl.sr.cmd &= ~HDLC_CMD_XME;
 	if (bcs->tx_skb->len > bcs->fifo_size) {
@@ -630,9 +629,7 @@
 
 	switch (pr) {
 	case PH_DATA | REQUEST:
-		if (bcs->tx_skb)
-			BUG();
-		
+		BUG_ON(bcs->tx_skb);
 		bcs->tx_skb = skb;
 		DBG_SKB(1, skb);
 		hdlc_fill_fifo(bcs);
diff --git a/drivers/isdn/hisax/hisax_isac.c b/drivers/isdn/hisax/hisax_isac.c
index f4972f6..81eac34 100644
--- a/drivers/isdn/hisax/hisax_isac.c
+++ b/drivers/isdn/hisax/hisax_isac.c
@@ -476,12 +476,10 @@
 	unsigned char cmd;
 	u_char *ptr;
 
-	if (!isac->tx_skb)
-		BUG();
+	BUG_ON(!isac->tx_skb);
 
 	count = isac->tx_skb->len;
-	if (count <= 0)
-		BUG();
+	BUG_ON(count <= 0);
 
 	DBG(DBG_IRQ, "count %d", count);
 
@@ -859,8 +857,7 @@
 			dev_kfree_skb(skb);
 			break;
 		}
-		if (isac->tx_skb)
-			BUG();
+		BUG_ON(isac->tx_skb);
 
 		isac->tx_skb = skb;
 		isac_fill_fifo(isac);
diff --git a/drivers/isdn/hisax/st5481_b.c b/drivers/isdn/hisax/st5481_b.c
index 657817a..22fd5db 100644
--- a/drivers/isdn/hisax/st5481_b.c
+++ b/drivers/isdn/hisax/st5481_b.c
@@ -356,9 +356,7 @@
 
 	switch (pr) {
 	case PH_DATA | REQUEST:
-		if (bcs->b_out.tx_skb)
-			BUG();
-		
+		BUG_ON(bcs->b_out.tx_skb);
 		bcs->b_out.tx_skb = skb;
 		break;
 	case PH_ACTIVATE | REQUEST:
diff --git a/drivers/isdn/hisax/st5481_d.c b/drivers/isdn/hisax/st5481_d.c
index 941f702..493dc94 100644
--- a/drivers/isdn/hisax/st5481_d.c
+++ b/drivers/isdn/hisax/st5481_d.c
@@ -596,9 +596,7 @@
 		break;
 	case PH_DATA | REQUEST:
 		DBG(2, "PH_DATA REQUEST len %d", skb->len);
-		if (adapter->d_out.tx_skb)
-			BUG();
-
+		BUG_ON(adapter->d_out.tx_skb);
 		adapter->d_out.tx_skb = skb;
 		FsmEvent(&adapter->d_out.fsm, EV_DOUT_START_XMIT, NULL);
 		break;
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index b9fed8a..a0927d1 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -974,8 +974,7 @@
 	int slot;
 	int proto;
 
-	if (net_dev->local->master)
-		BUG(); // we're called with the master device always
+	BUG_ON(net_dev->local->master); // we're called with the master device always
 
 	slot = lp->ppp_slot;
 	if (slot < 0 || slot >= ISDN_MAX_CHANNELS) {
@@ -2527,8 +2526,7 @@
 		printk(KERN_DEBUG "ippp: no decompressor defined!\n");
 		return skb;
 	}
-	if (!stat) // if we have a compressor, stat has been set as well
-		BUG();
+	BUG_ON(!stat); // if we have a compressor, stat has been set as well
 
 	if((master && *proto == PPP_COMP) || (!master && *proto == PPP_COMPFRAG) ) {
 		// compressed packets are compressed by their protocol type