Re: [PATCH 01/46] mm/mglru: don't use stack pointers when walking PUD and PMD tables

From: Rik van Riel

Date: Mon Oct 26 2026 - 21:34:17 EST


On Tue, 2026-10-27 at 00:17 +0100, David Hildenbrand (Arm) wrote:
> From: Josef Bacik <josef@xxxxxxxxxxxxxx>
>

> The fix is simple, so just fix the original commit so we don't have
> to
> speculate. To fix it, pass the actual PMD/PUD pointers. This restores
> the
> RCU-protected lookup and validation against the live PMD. Note that
> the PUD
> handling is required as well to handle folded page tables correctly
> in all
> cases.
>
> Fix generated by an LLM and sent by Josef Bacik in private.
>
> Fixes: bd74fdaea146 ("mm: multi-gen LRU: support page table walks")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> [ david: handle walk_pud_range() as well, clarify+simplify
> description,
>          adjust Fixes: ]
> Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxxx>

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