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.

7 files changed, 56 insertions, 14 deletions

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
diff --git a/sys/pci/if_mx.c b/sys/pci/if_mx.c
index 6ea96aa..8f43a5d 100644
--- a/sys/pci/if_mx.c
+++ b/sys/pci/if_mx.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_mx.c,v 1.28 1998/12/04 21:34:33 wpaul Exp $
+ *	$Id: if_mx.c,v 1.2 1998/12/04 21:48:12 wpaul Exp $
  */
 
 /*
@@ -94,7 +94,7 @@
 
 #ifndef lint
 static char rcsid[] =
-	"$Id: if_mx.c,v 1.28 1998/12/04 21:34:33 wpaul Exp $";
+	"$Id: if_mx.c,v 1.2 1998/12/04 21:48:12 wpaul Exp $";
 #endif
 
 /*
@@ -2028,6 +2028,12 @@ static void mx_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
diff --git a/sys/pci/if_pn.c b/sys/pci/if_pn.c
index efee8d1..a9796f8 100644
--- a/sys/pci/if_pn.c
+++ b/sys/pci/if_pn.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_pn.c,v 1.32 1998/11/29 06:40:07 wpaul Exp $
+ *	$Id: if_pn.c,v 1.1 1998/12/04 18:01:21 wpaul Exp $
  */
 
 /*
@@ -95,7 +95,7 @@
 
 #ifndef lint
 static char rcsid[] =
-	"$Id: if_pn.c,v 1.32 1998/11/29 06:40:07 wpaul Exp $";
+	"$Id: if_pn.c,v 1.1 1998/12/04 18:01:21 wpaul Exp $";
 #endif
 
 /*
@@ -1491,6 +1491,12 @@ static void pn_start(ifp)
 	}
 
 	/*
+	 * If there are no packets 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
diff --git a/sys/pci/if_tl.c b/sys/pci/if_tl.c
index 2df5676..840fe85 100644
--- a/sys/pci/if_tl.c
+++ b/sys/pci/if_tl.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_tl.c,v 1.18 1998/10/08 15:45:36 wpaul Exp $
+ *	$Id: if_tl.c,v 1.19 1998/10/31 17:23:48 wpaul Exp $
  */
 
 /*
@@ -218,7 +218,7 @@
 
 #ifndef lint
 static char rcsid[] =
-	"$Id: if_tl.c,v 1.18 1998/10/08 15:45:36 wpaul Exp $";
+	"$Id: if_tl.c,v 1.19 1998/10/31 17:23:48 wpaul Exp $";
 #endif
 
 #ifdef TL_DEBUG
@@ -2440,6 +2440,12 @@ static void tl_start(ifp)
 	}
 
 	/*
+	 * If there are no packets queued, bail.
+	 */
+	if (cur_tx == NULL)
+		return;
+
+	/*
 	 * That's all we can stands, we can't stands no more.
 	 * If there are no other transfers pending, then issue the
 	 * TX GO command to the adapter to start things moving.
diff --git a/sys/pci/if_vr.c b/sys/pci/if_vr.c
index a5a2fc4..a96d14c 100644
--- a/sys/pci/if_vr.c
+++ b/sys/pci/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
diff --git a/sys/pci/if_wb.c b/sys/pci/if_wb.c
index 41fc318..027365d 100644
--- a/sys/pci/if_wb.c
+++ b/sys/pci/if_wb.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_wb.c,v 1.30 1998/11/29 06:45:16 wpaul Exp $
+ *	$Id: if_wb.c,v 1.1 1998/12/04 18:01:21 wpaul Exp $
  */
 
 /*
@@ -121,7 +121,7 @@
 
 #ifndef lint
 static char rcsid[] =
-	"$Id: if_wb.c,v 1.30 1998/11/29 06:45:16 wpaul Exp $";
+	"$Id: if_wb.c,v 1.1 1998/12/04 18:01:21 wpaul Exp $";
 #endif
 
 /*
@@ -1752,6 +1752,12 @@ static void wb_start(ifp)
 	}
 
 	/*
+	 * If there are no packets 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
diff --git a/sys/pci/if_xl.c b/sys/pci/if_xl.c
index 8fbd6df..a3bbf22 100644
--- a/sys/pci/if_xl.c
+++ b/sys/pci/if_xl.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_xl.c,v 1.16 1998/10/22 16:46:26 wpaul Exp $
+ *	$Id: if_xl.c,v 1.17 1998/11/18 16:46:53 wpaul Exp $
  */
 
 /*
@@ -147,7 +147,7 @@
 
 #ifndef lint
 static char rcsid[] =
-	"$Id: if_xl.c,v 1.16 1998/10/22 16:46:26 wpaul Exp $";
+	"$Id: if_xl.c,v 1.17 1998/11/18 16:46:53 wpaul Exp $";
 #endif
 
 /*
@@ -2261,6 +2261,12 @@ static void xl_start(ifp)
 	}
 
 	/*
+	 * If there are no packets 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