Re: [PATCH 02/91] slub: fix panic with DISCONTIGMEM

From: David Rientjes
Date: Mon Feb 06 2012 - 16:59:23 EST

On Sun, 5 Feb 2012, Willy Tarreau wrote:

> commit 4a5fa3590f09999f6db41bc386bce40848fa9f63 upstream.
> Slub makes assumptions about page_to_nid() which are violated by
> DISCONTIGMEM and !NUMA. This violation results in a panic because
> page_to_nid() can be non-zero for pages in the discontiguous ranges and
> this leads to a null return by get_node(). The assertion by the
> maintainer is that DISCONTIGMEM should only be allowed when NUMA is also
> defined. However, at least six architectures: alpha, ia64, m32r, m68k,
> mips, parisc violate this. The panic is a regression against slab, so
> just mark slub broken in the problem configuration to prevent users
> reporting these panics.
> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
> Acked-by: Pekka Enberg <penberg@xxxxxxxxxx>
> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

The problem that this patch initially addressed is fixed by the next patch
in your series, "set memory ranges in N_NORMAL_MEMORY when onlined", so I
don't think this one should be merged.
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