Buggy network connection causes very low system responsiveness

[Adam Jackson]

On Tue, 2008-04-01 at 14:00 -0800, Jeff Spaleta wrote:

> I have a reproducible situation on F8 that you might find interesting.
> 
> 1) boot up into a NetworkManager enabled desktop, 
> 2) connect to a wireless network that has dhcp
> 3) gnome-terminal behaves normally
> 4) disable NM
> 5) connect a wired network cable for eth0
> 6) enable the network service configured to start eth0 using dhcp to a
> different network segment than the NM wireless connected to.
> 7) watch gnome-terminal take +30 seconds to spawn a window.

Dan Williams actually tracked this down a while ago.  Thank you for
reminding me, I'll push out an update for this.

For the perversely curious: X's session management protocol defines a
concept of a client ID, generated by the session leader and passed to
new clients.  Unfortunately, the spec defines the client ID in such a
way that you have to emit the IP address of the server in the ID, and
the way that gets implemented (hold your nose) is by calling
gethostname() followed by gethostbyname().  So if your resolver isn't
reachable (because the route is down, or because it changed and
gnome-session has the old one cached), or if your hostname isn't a
resolvable DNS name, you lose.

Thankfully the client ID is an opaque string prefixed by a version
number, so you can just bump the version number and use UUIDs.

- ajax