Re: [Xenomai-core] 2.6.17 hang on "will halt now" (possibly SMI related)

[Jan Kiszka <jan.kiszka@domain.hid>]

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Rodrigo Rosenfeld Rosas wrote:
> I began to experience a problem since 2.6.17 when shutting down my PC.
> 
> I noticed the problem just after I recompiled my kernel to enable the SMI 
> workaround. I, then rebooted the new kernel and when I tried to shutdown  the 
> system, it stopped on "will halt now" message or something like.
> 
> The same behavior is occurring both in home (Pentium-3 550 MHz) and  at 
> college (P4-1.7GHz). In both systems, Xenomai advised me to enable SMI 
> workaround. Actually, at home, the worst latency with the latency test was 
> about 20us independently from enabling or not the SMI workaround.
> 
> Do someone else experienced a similar problem when upgrading to 2.6.17?

Yep. Should be fixed now, see latest trunk.

It was a deadlock due to clumsy unregistration of the reboot notifier
from its own handler. I think the locking of the kernel changed in
2.6.17 (RCU) and made this fatal.

Jan


PS: 20us on a P-III 550 is a bit too good. I guess some serious load is
missing (cache load, IRQs, ...).


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