How do I find out what Ethernet network card drivers support the kernel debugging tool netdump in Red Hat Enterprise Linux 4?

Issue

How do I find out what Ethernet network card drivers support the kernel debugging tool netdump in Red Hat Enterprise Linux 4?

Environment

Red Hat Enterprise Linux 4

Resolution

The netdump kernel debugging tool requires that the network card driver supports the Netpoll infrastructure.

A simple way to check what drivers have this capability is to install the kernel-`uname -r`.EL.src.rpm package. Rebuild the source rpm by executing this command in /usr/src/redhat/SPECS:

rpmbuild -bp --target [arch] kernel-2.6.spec

Search the source code in /usr/src/redhat/BUILD/kernel-<version>/linux-<version> directory.

To search for the network card drivers that support Netpoll, issue the command to get a list of modules that support netdump for a list of modules that support netdump:

find . -name "*.c" -print | xargs grep CONFIG_NET_POLL_CONTROLLER | sort | uniq | awk -F: '{print $1}'  

If the system has any of the cards/chipsets for network devices listed in the results, it is very likely that Netpoll is supported and that netdump will work.

To see if the system's network interface uses any of these drivers, look in the file /etc/modprobe.conf:

# cat /etc/modprobe.conf
alias eth1 e100
alias eth0 8139too
alias sound-slot-0 i810_audio
...

Please note that even though the driver might support polling (and netdump), a VLAN interface using the driver won't work with netdump.

Generally speaking, a netdump configuration using VLANs is not supported.