Heikki Lindholm wrote:
 > >  o When and how does it crash? At start-up immediately? Or after a
 > >    while?
 > I inserted some serial debug prints and it gets two passes to 
 > eval_outer_loop done (enter/exit function). After that it freezes. 
 > Without the debug printing it dies with kernel access of illegal memory 
 > at xnpod_schedule, which btw. has been quite a common place to die.

A way to know a bit more about this error would be to have a look at the
exact address given by the kernel oops in the disassembly of
xnpod_schedule and try and find which pointer is invalid. This is not
very subtle, but sometimes works.

One reason why there used to be some invalid pointers accesses in
xnpod_schedule was when the context switch routine (on x86) forgot to
declare a few output or clobbered registers. In this case, the compiler
may assume that the contents of the registers are correct, whereas the
context switch clobbered them.


                                            Gilles Chanteperdrix.

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