Re: Oops in a driver while using SLUB as a SLAB allocator

From: Christoph Lameter
Date: Fri Jun 22 2007 - 13:27:04 EST


On Fri, 22 Jun 2007, Linus Torvalds wrote:

> > Looks like it would indeed address the immediate issue on ARM -
> > IF they've no particular reason to be using kmalloc there.
>
> I think the right thing to do is do both of these things. I already
> applied Hugh's patch - it seemed like a total nobrainer to do at this
> stage in the 2.6.22 -rc series. But that doesn't mean that we should not
> _also_ look at "flush_dcache_page()" users.

Hugh's patch not address the complete issue. It only works right now
because the size of the allocation is page size and fits right into a slab
page. If debugging is enabled then the slab size will increase and the
"pages" will be misaligned which will lead to other sorts of funky
behavior. kmalloc allocations are only guaranteed to be aligned to
ARCH_KMALLOC_MINALIGN which is 4 to 8 bytes. If one must have a
page aligned entity out of a slab allocator then a custom slab needs to be
created.
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