On Sun, Feb 25, 2007 at 11:01:06PM -0500, David Woodhouse wrote:

Yeah, I did that before giving up on it for the day and going in search
of dinner. It changes the failure mode to a BUG() in
cache_free_debugcheck(), at line 2876 of mm/slab.c
It smells like the pages weren't actually reserved in the first place
and we were blithely allocating them. The only problem with that theory
is that the initrd doesn't seem to be getting corrupted -- and if we
were handing out its pages like that then surely _something_ would have
scribbled on it before we tried to read it.
When I head back in tomorrow morning I'll instrument free_initrd_mem()
to check that the PageReserved bit was actually set on each page, before
clearing it. And I'll make the page allocation routines check whether
they're giving out pages between initrd_start and initrd_end, etc.

Another few things to try would be inserting checks in page_alloc.c for
pages in that specific range before some flag set in free_initrd_mem()
is set, and (conflicting with that, though easily reconciled) unmapping
initrd memory in free_initrd_mem() instead of freeing it.


-- wli