Re: Race betwen the NMI handler and the RTC clock in practially allkernels II

[Corey Minyard]

Maciej W. Rozycki wrote:

> > And you need a mutex for SMP systems.  If one processor is handling an 
> > NMI, another processor may still be accessing the device.
> >    
> Actually this path is meant to be ever accessed by one CPU only (one that
> has its LINT1 line enabled), but it may be reached by other ones due to
> the NMI watchdog as code does not check if its run by the right processor.  
> This probably qualifies as a bug.  Only the watchdog code of the NMI
> handler is expected to run everywhere.
>  
Yes, only one processor will run through the NMI code, but another 
processor may be accessing the RTC or something else in CMOS.  The mutex 
will prevent the NMI and the RTC access from conflicting.

-Corey
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