Re: [PATCH] bootmem: avoid freeing to bootmem after bootmem is done

[Mel Gorman]

On Fri, Jul 24, 2015 at 04:53:46PM -0400, Chris Metcalf wrote:
> Bootmem isn't popular any more, but some architectures still use
> it, and freeing to bootmem after calling free_all_bootmem_core()
> can end up scribbling over random memory.  Instead, make sure the
> kernel panics by ensuring the node_bootmem_map field is non-NULL
> when are freeing or marking bootmem.
> 
> An instance of this bug was just fixed in the tile architecture
> ("tile: use free_bootmem_late() for initrd") and catching this case
> more widely seems like a good thing.
> 
> Signed-off-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>

In general it looks fine  but you could just WARN_ON, return and still
boot the kernel too. Obviously it would need to be fixed but Linus will
push back if he spots a BUG_ON when there was a recovery option.

-- 
Mel Gorman
SUSE Labs
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