linux-kernel - Re: [PATCH v2 4/8] selftests/mm: fix usage of FORCE

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Message-ID: <e2d76567-44f3-4372-9490-5cae91619125@kernel.org>
Date: Mon, 19 Jan 2026 11:50:15 +0100
From: "David Hildenbrand (Red Hat)" <david@...nel.org>
To: Kevin Brodsky <kevin.brodsky@....com>, linux-mm@...ck.org,
 linux-kselftest@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, Andrew Morton <akpm@...ux-foundation.org>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, Mark Brown
 <broonie@...nel.org>, Ryan Roberts <ryan.roberts@....com>,
 Shuah Khan <shuah@...nel.org>
Subject: Re: [PATCH v2 4/8] selftests/mm: fix usage of FORCE_READ() in cow
 tests

On 1/7/26 17:48, Kevin Brodsky wrote:
> Commit 5bbc2b785e63 ("selftests/mm: fix FORCE_READ to read input
> value correctly") modified FORCE_READ() to take a value instead of a
> pointer. It also changed most of the call sites accordingly, but
> missed many of them in cow.c. In those cases, we ended up with the
> pointer itself being read, not the memory it points to.
> 
> No failure occurred as a result, so it looks like the tests work
> just fine without faulting in. However, the huge_zeropage tests
> explicitly check that pages are populated, so those became skipped.

Right, that's nasty! Thanks!

For all cases, we could probably just fail if the memory is not 
populated after FORCE_READ().

Would you have time to prepare a patch for that?

Acked-by: David Hildenbrand (Red Hat) <david@...nel.org>

-- 
Cheers

David