Re: [PATCH v3] selftests/mm: add folio_split() and filemap_get_entry() race test

[Andrew Morton]

On Thu, 19 Mar 2026 15:04:08 -0400 Zi Yan <ziy@xxxxxxxxxx> wrote:

> The added folio_split_race_test is a modified C port of the race condition
> test from [1]. The test creates shmem huge pages, where the main thread
> punches holes in the shmem to cause folio_split() in the kernel and
> a set of 16 threads reads the shmem to cause filemap_get_entry() in the
> kernel. filemap_get_entry() reads the folio and xarray split by
> folio_split() locklessly. The original test[2] is written in rust and uses
> memfd (shmem backed). This C port uses shmem directly and use a single
> process.
> 
> Note: the initial rust to C conversion is done by Cursor.

Sashiko has questions:
	https://sashiko.dev/#/patchset/20260319190409.294523-1-ziy%40nvidia.com

(this is getting painful :(.  I hope they're worthwhile)