page size assertion

Michael Hohmuth hohmuth at
Fri Dec 4 13:29:19 CET 1998

> Eiji Ota <age at> writes:
> > > > > I'm interested in this fantastic work(of course, L4). When I tried to
> > > > > feel it, I faced an assertion failed by assert(size == PAGE_SIZE) in
> > > > > line).
> > > > > 
> > > > > The wrong page size seemed to be passed by fpage_map in as
> > > > > a SUPERPAGE_SIZE, but I don't find the root cause for this trouble.

I wrote:

> I think I have a theory on what the problem in Fiasco is (more on that 
> below).  However, it would still be useful to know what the system is
> trying to do when the error occurs; this would help me to reproduce
> and track down the problem.
> My theory is that we fail to test rigorously enough that a receiver
> really has enough space in its virtual address space to take a
> superpage mapping.  I think we currently test that just 4K are
> unmapped in the receiver (that is, no mapping exists for the target
> virtual address); that's not enough.

Please try the patch appended below.

I still would like to know which program triggers this problem as I
have not been able to reproduce it.

hohmuth at, hohmuth at

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