When are machine checks suppose to be recoverable?

Kumar Gala kumar.gala at freescale.com
Wed Aug 24 03:04:38 EST 2005

On Aug 23, 2005, at 11:43 AM, David Woodhouse wrote:

> On Mon, 2005-08-22 at 23:56 -0300, Marcelo Tosatti wrote:
>> "My dual G4 PowerMac crashes sometimes when it probes for the  
>> (absent)
>> serial ports. Theoretically it's supposed to take a machine check and
>> recover -- but it doesn't always work like that."
>> Maybe you just need the proper entry in the exception table for IO
>> inb/outb?
>> Is there a stacktrace, David?
> No, just a silent death when probing for one of the serial ports;
> usually not the first. It doesn't seem to even make it into the  
> machine
> check handler. Adding printks into serial_inb and serial_outb makes it
> much less likely to happen -- could be something bizarre about  
> alignment
> of the instructions which cause the machine check, or time elapsed  
> from
> one machine check to the next.

If the machine is locking hard it could be check stopping due to  
getting a second machine check.

- kumar

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