[vbox-dev] e1000 assertion failure transmitting on a down interface

[Ed Maste]

VirtualBox 4.2.0
Host: FreeBSD 9.1-PRELEASE r240994M
Guest: FreeBSD 10.0-CURRENT r241736M (with netmap enabled)

Network configuration is an 82540EM, cable connected and no attachment.

If I leave the interface (em0) down in the guest and try to transmit
via netmap I trigger an assertion failure in e1kTxQueueConsumer.

49:05:09.246948 !!Assertion Failed!!
49:05:09.246949 Expression: RT_SUCCESS(rc) || rc == VERR_TRY_AGAIN
49:05:09.246950 Location  :
/data2/emaste/redports-emaste/emulators/virtualbox-ose/work/VirtualBox-4.2.0/src/VBox/Devices/Network/DevE1000.cpp(5153)
bool e1kTxQueueConsumer(PDMDEVINS*, PDMQUEUEITEMCORE*)
49:05:09.247001 VERR_NET_DOWN

One interesting observation is that this only happens when attempting
to transmit a 2nd packet - the first does not trigger the assertion.

-Ed