Re: [PATCH] mm/pagewalk: fix race between concurrent split and refault

[Boone, Max]

> On Mar 18, 2026, at 2:08 PM, Max Boone <mboone@xxxxxxxxxx> wrote:
>> 
>> Yikes, really? :) This is from 2017, I'm a little surprised we didn't hit
>> this bug until now.
>> 
>> Has something changed more recently that made it more likely to hit? Or is
>> it one of those 'needed people to have more RAM first' or bigger PCI BAR's?

Forgot to mention, but yeah, we’re seeing this on Blackwell cards which have very
large BARs, so probably seeing it first because of that. But the window was already
pretty small, it’s not a very logical thing to poll numa_maps or smaps walks while the
firmware of a VM is remapping the BARs of a GPU. With regards to that specific case
there’s a proxmox thread and mail from the same person presumably [1, 2] that mentions 
the same bug.

[1] https://forum.proxmox.com/threads/walk_pgd_range-crash-pve9-1-on-6-18.179895/
[2] https://lore.kernel.org/all/5948f3a6-8f30-4c45-9b86-2af9a6b37405@xxxxxxxxxx/

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