[PATCH v6 03/10] mm/memory_hotplug: Don't access uninitialized memmaps in shrink_pgdat_span()

David Hildenbrand david at redhat.com
Mon Oct 14 20:31:14 AEDT 2019


On 06.10.19 10:56, David Hildenbrand wrote:
> We might use the nid of memmaps that were never initialized. For
> example, if the memmap was poisoned, we will crash the kernel in
> pfn_to_nid() right now. Let's use the calculated boundaries of the separate
> zones instead. This now also avoids having to iterate over a whole bunch of
> subsections again, after shrinking one zone.
> 
> Before commit d0dc12e86b31 ("mm/memory_hotplug: optimize memory
> hotplug"), the memmap was initialized to 0 and the node was set to the
> right value. After that commit, the node might be garbage.
> 
> We'll have to fix shrink_zone_span() next.
> 
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Cc: Oscar Salvador <osalvador at suse.de>
> Cc: David Hildenbrand <david at redhat.com>
> Cc: Michal Hocko <mhocko at suse.com>
> Cc: Pavel Tatashin <pasha.tatashin at soleen.com>
> Cc: Dan Williams <dan.j.williams at intel.com>
> Cc: Wei Yang <richardw.yang at linux.intel.com>
> Fixes: d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug")

@Andrew, can you convert that to

Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visible after d0dc12e86b319

and add

Cc: stable at vger.kernel.org # v4.13+

-- 

Thanks,

David / dhildenb


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