Re: [PATCHv2] x86: fix the initialization of physnode_map

From: David Rientjes
Date: Sat Feb 01 2014 - 18:46:29 EST

On Sat, 1 Feb 2014, Petr Tesarik wrote:

> With DISCONTIGMEM, the mapping between a pfn and its owning node is
> initialized using data provided by the BIOS. However, the initialization
> may fail if the extents are not aligned to section boundary (64M).
> The symptom of this bug is an early boot failure in pfn_to_page(),
> as it tries to access NODE_DATA(__nid) using index from an unitialized
> element of the physnode_map[] array.
> While the bug is always present, it is more likely to be hit in kdump
> kernels on large machines, because:
> 1. The memory map for a kdump kernel is specified as exactmap, and
> exactmap is more likely to be unaligned.
> 2. Large reservations are more likely to span across a 64M boundary.
> Signed-off-by: Petr Tesarik <ptesarik@xxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
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