From f72fa84f9303d83d38279ea0ca986be9cf5a47b2 Mon Sep 17 00:00:00 2001
From: wpaul <wpaul@FreeBSD.org>
Date: Sat, 5 Dec 1998 02:21:44 +0000
Subject: Add sanity check to foo_start() routines: in the unlikely (though
 apparently possible) event that the transmit start routine is called with and
 empty if_snd queue, bail out instead of dereferencing unilitialized transmit
 list pointers and panicking.

---
 sys/dev/vr/if_vr.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

(limited to 'sys/dev/vr')

diff --git a/sys/dev/vr/if_vr.c b/sys/dev/vr/if_vr.c
index a5a2fc4..a96d14c 100644
--- a/sys/dev/vr/if_vr.c
+++ b/sys/dev/vr/if_vr.c
@@ -29,7 +29,7 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  *
- *	$Id: if_vr.c,v 1.13 1998/12/01 22:08:11 wpaul Exp $
+ *	$Id: if_vr.c,v 1.1 1998/12/04 18:01:21 wpaul Exp $
  */
 
 /*
@@ -97,7 +97,7 @@
 
 #ifndef lint
 static char rcsid[] =
-	"$Id: if_vr.c,v 1.13 1998/12/01 22:08:11 wpaul Exp $";
+	"$Id: if_vr.c,v 1.1 1998/12/04 18:01:21 wpaul Exp $";
 #endif
 
 /*
@@ -1627,6 +1627,12 @@ static void vr_start(ifp)
 	}
 
 	/*
+	 * If there are no frames queued, bail.
+	 */
+	if (cur_tx == NULL)
+		return;
+
+	/*
 	 * Place the request for the upload interrupt
 	 * in the last descriptor in the chain. This way, if
 	 * we're chaining several packets at once, we'll only
-- 
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