[PATCH 14/46] mm/huge_memory: fix zapping migration entries for device-private THPs

[sashiko-bot at kernel.org]

> From: Chris Mason <mason at kernel.org>
> 
> A PMD migration entry can refer to a device-private folio.
> zap_huge_pmd_folio() checks the folio type instead of the entry type,
> so it treats such a migration entry as a device-private entry.
> 
> Installing the migration entry already removed the reverse mapping and
> dropped the mapping reference. Zapping it must not repeat those
> operations. Concurrent MADV_DONTNEED during migration back to system
> memory can trigger this.
> 
> Check the PMD entry type using pmd_is_device_private_entry().
> 
> Fix generated by an LLM and sent by Chris Mason in private.
> 
> Fixes: 368076f52ebe ("mm/huge_memory: add device-private THP support to PMD operations")
> Cc: stable at vger.kernel.org
> Signed-off-by: Chris Mason <mason at kernel.org>
> [ david: simplify description ]
> Signed-off-by: David Hildenbrand (Arm) <david at kernel.org>

Sashiko has reviewed this patch and found no issues.

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