Description of problem:

After resume from suspend, one CPU goes to 100% and /var/log/messages is filled up with

invalid PHY speed/duplex: 0xffff
invalid PHY speed/duplex: 0xffff
invalid PHY speed/duplex: 0xffff
...


[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 146509063 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 147332808 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 147865283 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 148349403 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 148782318 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 149265678 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 151087018 Sep 25 08:38 messages
[root@oboe log]# ls -la messages
-rw-r--r--. 1 root root 151902023 Sep 25 08:39 messages

Kernel:

[root@oboe log]# uname -a
Linux oboe.localdomain 3.11.1-200.fc19.x86_64 #1 SMP Sat Sep 14 15:04:51 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

Apparently related to the alx kernel module

It is the same bug as reported here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1213009
https://bbs.archlinux.org/viewtopic.php?pid=1328254

It worked fine with kernel 3.10.x but fails with the new 3.11.x

As this is a showstopper, I need to go back to use kernel 3.10.x