From: Kevin Brodsky <kevin.brodsky@arm.com>
To: "David Hildenbrand (Red Hat)" <david@kernel.org>,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Mark Brown <broonie@kernel.org>,
Ryan Roberts <ryan.roberts@arm.com>,
Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH v2 4/8] selftests/mm: fix usage of FORCE_READ() in cow tests
Date: Mon, 19 Jan 2026 14:24:03 +0100 [thread overview]
Message-ID: <4d3361e4-90e8-409f-bde5-b09de53137b1@arm.com> (raw)
In-Reply-To: <e2d76567-44f3-4372-9490-5cae91619125@kernel.org>
On 19/01/2026 11:50, David Hildenbrand (Red Hat) wrote:
> 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?
Sure, I guess we could even have a helper that performs a FORCE_READ()
and then returns the result of pagemap_is_populated().
- Kevin
next prev parent reply other threads:[~2026-01-19 13:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-07 16:48 [PATCH v2 0/8] Various mm kselftests improvements/fixes Kevin Brodsky
2026-01-07 16:48 ` [PATCH v2 1/8] selftests/mm: default KDIR to build directory Kevin Brodsky
2026-01-07 16:48 ` [PATCH v2 2/8] selftests/mm: remove flaky header check Kevin Brodsky
2026-01-07 16:48 ` [PATCH v2 3/8] selftests/mm: pass down full CC and CFLAGS to check_config.sh Kevin Brodsky
2026-01-07 16:59 ` Mark Brown
2026-01-07 16:48 ` [PATCH v2 4/8] selftests/mm: fix usage of FORCE_READ() in cow tests Kevin Brodsky
2026-01-08 0:56 ` SeongJae Park
2026-01-08 2:04 ` wang lian
2026-01-08 2:07 ` [PATCH v2 7/8] selftests/mm: fix exit code in pagemap_ioctl wang lian
2026-01-19 10:50 ` [PATCH v2 4/8] selftests/mm: fix usage of FORCE_READ() in cow tests David Hildenbrand (Red Hat)
2026-01-19 13:24 ` Kevin Brodsky [this message]
2026-01-22 5:40 ` Dev Jain
2026-01-07 16:48 ` [PATCH v2 5/8] selftests/mm: introduce helper to read every page in range Kevin Brodsky
2026-01-09 1:30 ` SeongJae Park
2026-01-12 9:37 ` Kevin Brodsky
2026-01-13 0:55 ` SeongJae Park
2026-01-19 10:55 ` David Hildenbrand (Red Hat)
2026-01-19 13:29 ` Kevin Brodsky
2026-01-22 6:05 ` Dev Jain
2026-01-07 16:48 ` [PATCH v2 6/8] selftests/mm: fix faulting-in code in pagemap_ioctl test Kevin Brodsky
2026-01-19 11:09 ` David Hildenbrand (Red Hat)
2026-01-19 13:30 ` Kevin Brodsky
2026-01-22 6:16 ` Dev Jain
2026-01-07 16:48 ` [PATCH v2 7/8] selftests/mm: fix exit code in pagemap_ioctl Kevin Brodsky
2026-01-08 1:06 ` SeongJae Park
2026-01-08 2:12 ` wang lian
2026-01-22 6:22 ` Dev Jain
2026-01-07 16:48 ` [PATCH v2 8/8] selftests/mm: report SKIP in pfnmap if a check fails Kevin Brodsky
2026-01-12 9:34 ` Ryan Roberts
2026-01-12 10:03 ` Kevin Brodsky
2026-01-12 10:25 ` Ryan Roberts
2026-01-19 11:16 ` David Hildenbrand (Red Hat)
2026-01-19 14:26 ` Ryan Roberts
2026-01-19 14:32 ` David Hildenbrand (Red Hat)
2026-01-20 16:27 ` Ryan Roberts
2026-01-21 13:45 ` Kevin Brodsky
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