Cisco VPN client freezes computer when using wireless wlan0

Installation, configuration and troubleshooting of the Cisco VPN Client on Linux systems

Re: Cisco VPN client freezes computer when using wireless wlan0

Postby tuxx-home.at » Tue Mar 18, 2008 5:06 pm

Thanks for providing this information here although I'm not too much into this kernel hacking stuff and therefore can't make any use out of these log lines ;)
Maybe someone else is able to, the only thing I can see is that it does some magic with softirqs which might be caused by SMP-specific stuff.

Could you please try one of my above mentioned "switch-one-cpu-off" fixes and confirm that the problem goes away when turning off SMP?
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Re: Cisco VPN client freezes computer when using wireless wlan0

Postby jch » Thu Mar 20, 2008 12:16 pm

Turning off one CPU seems to fix the problem. The stack trace I gave earlier, Cisco's stated lack of support for SMP kernels :-( and that fact rather suggest that the closed-source Cisco source code is not SMP-safe. Well, I guess that's obvious. Something to look at over the Easter weekend anyway...

I also suspect, however, that even when running on just one CPU that there will be occasional crashes because the Fedora kernel (at least) can be pre-empted.

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Re: Cisco VPN client freezes computer when using wireless wlan0

Postby tuxx-home.at » Sun Mar 23, 2008 11:35 am

I don't think that pre-emption is the problem. I don't even have the problem with SMP configurations on my notebook (Intel Dual Core something), I can use the VPN client without any hacks over wired and wireless connections without having my system freezing after a few minutes.

Disabling SMP might fix this issue for most users but I don't think that it is really caused by SMP but maybe by something else which just gets eliminated by disabling SMP support.
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