Re: When are machine checks suppose to be recoverable?

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

On Mon, 2005-08-22 at 23:56 -0300, Marcelo Tosatti wrote:

quoted

"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