Re: DEBUG_PAGEALLOC + order-10 alloc/free_pages = lockup

[Arjan van de Ven]

Ingo Molnar wrote:
> * Tony Battersby <tonyb@xxxxxxxxxxxxxxx> wrote:
>
> > An order-10 alloc_pages followed by free_pages with DEBUG_PAGEALLOC
> > causes a lockup during subsequent memory allocations.  Order-9 and lower
> > do not trigger the problem.  This problem was introduced in 2.6.25-rc1
> > and fixed in 2.6.28-rc1.  Even though the bug is now fixed, I am
> > reporting it because:
> >
> > 1) I am not sure that anyone ever realized that the bug existed.
>
> Correct.
>
> > 2) I want to make sure that the bug is really fixed and not just hidden
> >    from view.
>
> i think it got hidden. Apparently splitting up a large kernel linear page 
> in IRQ context has a bug. I dont see it immediately what it could be - 
> Thomas, Suresh, do you have any ideas?
>
> > 3) To see if anyone thinks that the fix should be included in
> >    2.6.27 -stable.
>
> if 0b8fdcbcd287a1fbe66817491e6149841ae25705 applies cleanly to .27 -stable 
> then i'd agree it should be added. If there's lots of dependencies then 
> maybe not.

I also wonder who is doing an order 10 allocation... that'd worry me ;)

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