On Fri, Dec 22, 2006 at 01:31:26AM +0100, Segher Boessenkool wrote:
> > + if (len > TASK_SIZE)
> > + return -ENOMEM;
>
> Shouldn't that be addr+len instead? The check looks incomplete
> otherwise. And you meant ">=" I guess?
No. Have a look at the other hugetlb_get_unmapped_area()
implementations. Because this is in the get_unmapped_area() path,
'addr' is just a hint, so checking addr+len would give bogus
failures. This test is, I believe, essentially an optimization - if
it fails, we're never going to find a suitable addr, so we might as
well give up now.
> > - /* Paranoia, caller should have dealt with this */
> > - BUG_ON((addr + len) > 0x100000000UL);
> > -
>
> Any real reason to remove the paranoia check? If it's trivially
> always satisfied, the compiler will get rid of it for you :-)
Yes - this is the very bug on which was causing crashes - the "caller
should have dealt with this" comment is wrong. The test has been
moved into htlb_check_hinted_area() and now simply fails (and so falls
back to searching for a suitable address), rather than BUG()ing.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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