[PATCH 4/6] Under conditions of high load and low resources, it was possible for NDIS (in combination with overlying drivers) to send NET_BUFFER_LIST structures containing NULL MDL's for transmission. This resulted in an immediate bugcheck.

[Martin Harvey <Martin.Harvey@xxxxxxxxxx>]

This patch contains the immediate proximate fix for this particular
issue, instead failing the send with STATUS_INVALID_PARAMETER.

Signed-off-by: Martin Harvey <martin.harvey@xxxxxxxxxx>
---
 src/xenvif/transmitter.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/xenvif/transmitter.c b/src/xenvif/transmitter.c
index 724615d..ea1282c 100644
--- a/src/xenvif/transmitter.c
+++ b/src/xenvif/transmitter.c
@@ -5148,13 +5148,17 @@ TransmitterQueuePacket(
     PXENVIF_TRANSMITTER_RING        Ring;
     NTSTATUS                        status;
 
+    status = STATUS_INVALID_PARAMETER;
+    if (Mdl == NULL)
+        goto fail1;
+
     Frontend = Transmitter->Frontend;
 
     Packet = __TransmitterGetPacket(Transmitter);
 
     status = STATUS_NO_MEMORY;
     if (Packet == NULL)
-        goto fail1;
+        goto fail2;
 
     Packet->Mdl = Mdl;
     Packet->Offset = Offset;
@@ -5206,6 +5210,9 @@ TransmitterQueuePacket(
 
     return STATUS_SUCCESS;
 
+fail2:
+    Error("fail2\n");
+
 fail1:
     Error("fail1 (%08x)\n", status);
 
-- 
2.25.0.windows.1