[systemd-devel] Renaming network interfaces: device or resource busy

[Thomas Bächler]

Am 30.09.2013 17:14, schrieb Colin Guthrie:
> Hi,
> 
> Just trying to debug the problem mentioned in the subject. I'm wanting
> to use the new device names in stage 2 of our installer (some closing
> config routines write the interface name into some conf files etc), but
> when udev rules kick in, the device is already up and in use... is there
> any way to work out what is using it and preventing the rename?
> 
> I would guess fuser or netstat but not quite sure what to look for.
> Simply running netstat only shows unix sockets, no tcp/udp ones...
> 
> Any help appreciated.

Any application that listens on netlink for new network interfaces may
start using the interface before udev has finished processing the uevent.

IMO, this needs to be fixed in the kernel and udev, so that udev can
have a chance to finish its uevent processing before the interface is
announced via netlink. As far as I know, no work in that direction has
been done.

We had such a problem when running dhcpcd without an interface argument:
Depending on whether udev or dhcpcd was faster, interface renaming would
succeed or fail. We are now working around this issue ([1]), but I don't
particularly like that solution.

[1]
https://projects.archlinux.org/archiso.git/commit/?id=7d14796716939fbabb9daba6b6f5294016d63cd4

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