Re: REGRESSION for RT2561/RT61 in 2.6.32

[Gertjan van Wingerde <gwingerde@gmail.com>]

On Tue, Dec 8, 2009 at 3:27 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Mon, 7 Dec 2009, Gertjan van Wingerde wrote:
>
>> > While the system is hung, Alt-SysRq-keys still work but nothing else
>> > shows up when I type (using a VT console, not X).  However I don't know
>> > what debugging to do or what to look for.
>> >
>> > Under 2.6.31 everything works okay.
>> >
>>
>> Hmmm, that's odd. I haven't seen any other reports on this (on full system hangs that is).
>>
>> It would be very hard to figure out what is going wrong without any form of logging of
>> an oops or something. Is there any way you can find out if any oops information is present?
>
> There is no oops.  The system just stops responding to keystrokes other
> than Alt-SysRq-*.
>
>> What does Alt-SysRq-l tell us, what are the CPU's doing when the system is hung?
>
> Unfortunately Alt-SysRq-l wasn't very helpful.  The output is below
> (captured using a serial console), starting from when I configured the
> wireless interface.  For thoroughness I have also attached the output
> of Alt-SysRq-T in single-user mode, but it doesn't seem to contain
> anything striking.
>
> Could the problem be connected with CONFIG_4KSTACKS (which was enabled
> in this kernel)?

Hmm, the stack overrun seems to be generated as part of the
Alt-SysRq-* handling, not of any rt61pci handling.

I noticed in the Alt-SysRq-T output that powersaving is enabled. We've
seen some strange behaviour on this, so could you disable that with:

iwconfig wlan0 power off

or run a kernel in which CONFIG_CFG80211_DEFAULT_PS is disabled.

Maybe that will fix the problem we are seeing?

Other than that I have no ideas on what is happening here.

---
Gertjan.