pidgin and VPN issues.

[Ethan Blanton]

Richard Allen spake unto us the following wisdom:
> For some reason this has been happening much less frequently the last
> couple of weeks.  But I did see this just a few minutes ago. The UI
> gets complete frozen, but it does continue to update itself when I
> pull a chat window to the forground from behind another window.  It
> prints out no new messages or does not accept input.  I cant even
> select contacts in the buddy list.
> 
> I dont know how long pidgin had been frozen but I did start trying to
> debug.  I first attached a strace to the process:

This is good sleuthing!

> [ra at hamburger ~]$ ps -ef | grep pidgin
> ra        2694  2267  0 01:14 ?        00:05:53 pidgin
> 
> [ra at hamburger ~]$ strace -p 2694
> Process 2694 attached
> sendto(19, "\241h\366\223\272\251\21\23\255\26l9\370p\255\300\214\376\322y\221k\341\3507\16\202\200}~%\301"...
> , 679, 0, NULL, 0) = -1 EAGAIN (Resource temporarily unavailable)
> 
> Huge, endless list of that..

Your intuition that we need to look at fd 19 is great.

> [ra at hamburger ~]$ ll /proc/2694/fd/19 
> l-wx------. 1 ra ra 64 May 11 01:14 /proc/2694/fd/19 -> /home/ra/.purple/logs/sipe/ra at ok.is%2cok%5cra/.system/2013-05-11.125047+0000GMT.txt

This is interesting.  Is /home/ra/.purple/logs on a local disk, or
network mounted?  What filesystem?  You really shouldn't see a jillion
EAGAINs on filesystem write, and I'm quite surprised to see those
sendtos.  If this is a network filesystem, I suspect the server (or
the network) was out to lunch.

Does /var/log/messages or /var/log/dmesg say anything interesting from
around the time that this happened?  Any disk errors or timeouts?

> I then tried to attach gdb to the process but gdb told me I needed the
> debuginfo packages (I'm a Fedora user) so I disconnected gdb and
> installed the needed packages. This is where a miracle happened.
> pidgin recovered from the infinite loop and proceeded working as
> normal. I am however ready to hook up gdb the next time this happens.

That certainly won't hurt.

Ethan
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