kern/89073: em(4) continual "em0: RX overrun" warnings

Vivek Khera vivek at
Tue Nov 15 15:20:26 GMT 2005

>Number:         89073
>Category:       kern
>Synopsis:       em(4) continual "em0: RX overrun" warnings
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Nov 15 15:20:21 GMT 2005
>Originator:     Vivek Khera
>Release:        FreeBSD 6.0-RELEASE amd64
System: FreeBSD 6.0-RELEASE FreeBSD 6.0-RELEASE #2: Thu Nov 3 15:47:50 EST 2005 vivek at amd64

Hardware is Dual Opteron Tyan K8SR motherboard with Intel dual port gigabit
NIC plugged in.  Onboard bge ethernet is disabled in BIOS.  Other card is an
LSI 320-2X RAID card.


I have an identical system (with two fewer disks, though) running 5.4-RELEASE
which runs non-stop.  This system I installed 6.0-REL and it runs really well
and the disk I/O is much faster.  However, if I do any kind of network access
I get "em0: RX overrun" warnings in the log at a pretty high rate.  This can
be caused by doing something so simple as running a buildworld with /usr/src
mounted via NFS and /usr/obj being a local disk.  The kernel is GENERIC as
installed by the 6.0-REL CD.

Ultimately, the machine becomes non-responsive to the network.  For some
reason the serial console is not working past the BIOS boot, so I can't see if
the machine is hung totally or just the network (the machine is at a co-lo
facility)  I'll be attempting to fix the serial console soon.

The em0 is conected to a Dell gigabit switch which is working fine (same port
was used for another system with no issues) and the NFS server is on a
different switch running 100baseT.


run "buildworld" with NFS mounted /usr/src.



Not sure.  Trying a new NIC later today as soon as it arrives.


More information about the freebsd-bugs mailing list