From: Shuai Xue <xueshuai@linux•alibaba.com>
To: Ruidong Tian <tianruidong@linux•alibaba.com>,
catalin.marinas@arm•com, will@kernel•org, rafael@kernel•org,
tony.luck@intel•com, guohanjun@huawei•com, mchehab@kernel•org,
tongtiangen@huawei•com, james.morse@arm•com,
robin.murphy@arm•com, andreyknvl@gmail•com, dvyukov@google•com,
vincenzo.frascino@arm•com, mpe@ellerman•id.au, npiggin@gmail•com,
ryabinin.a.a@gmail•com, glider@google•com,
christophe.leroy@csgroup•eu, aneesh.kumar@kernel•org,
naveen.n.rao@linux•ibm.com, tglx@linutronix•de, mingo@redhat•com
Cc: linux-arm-kernel@lists•infradead.org, linux-mm@kvack•org,
linuxppc-dev@lists•ozlabs.org, linux-kernel@vger•kernel.org,
kasan-dev@googlegroups•com
Subject: Re: [PATCH v14 6/8] lib/test: memcpy_kunit: add copy_page() and copy_mc_page() tests
Date: Wed, 27 May 2026 21:43:52 +0800 [thread overview]
Message-ID: <f75d7ff8-d965-4f17-8548-2525512a400a@linux.alibaba.com> (raw)
In-Reply-To: <20260518084956.2538442-7-tianruidong@linux.alibaba.com>
On 5/18/26 4:49 PM, Ruidong Tian wrote:
> Add KUnit tests for copy_page() and copy_mc_page(), modeled after
> the existing memcpy_test() style: a static page-aligned src and a
> two-page dst, filled with random bytes plus non-zero edges, then
> verify byte-for-byte equality and that the adjacent page is
> untouched. The copy_mc_page() case additionally checks the return
> value is 0 on clean memory and is gated on CONFIG_ARCH_HAS_COPY_MC.
>
> Signed-off-by: Ruidong Tian <tianruidong@linux•alibaba.com>
> ---
> lib/tests/memcpy_kunit.c | 67 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 66 insertions(+), 1 deletion(-)
>
> diff --git a/lib/tests/memcpy_kunit.c b/lib/tests/memcpy_kunit.c
> index d36933554e46..85df53ccfb0c 100644
> --- a/lib/tests/memcpy_kunit.c
> +++ b/lib/tests/memcpy_kunit.c
> @@ -493,6 +493,67 @@ static void memmove_overlap_test(struct kunit *test)
> }
> }
>
> +/* --- Page-sized copy tests --- */
> +
> +static u8 page_src[PAGE_SIZE] __aligned(PAGE_SIZE);
> +static u8 page_dst[PAGE_SIZE * 2] __aligned(PAGE_SIZE);
> +static const u8 page_zero[PAGE_SIZE] __aligned(PAGE_SIZE);
> +
> +static void init_page(struct kunit *test)
> +{
> + /* Get many bit patterns. */
> + get_random_bytes(page_src, PAGE_SIZE);
> +
> + /* Make sure we have non-zero edges. */
> + set_random_nonzero(test, &page_src[0]);
> + set_random_nonzero(test, &page_src[PAGE_SIZE - 1]);
> +
> + /* Explicitly zero the entire destination. */
> + memset(page_dst, 0, ARRAY_SIZE(page_dst));
init_page() memsets the entire two-page page_dst to zero, and the
test then asserts the second page is still zero. A buggy copy_page()
that overwrites the second page with bytes that happen to include a
zero byte would still pass.
Please fill page_dst with a non-zero sentinel (e.g. 0xA5) instead
of zero, and check the second half against that sentinel using
memchr_inv():
memset(page_dst, 0xA5, ARRAY_SIZE(page_dst));
...
KUNIT_ASSERT_TRUE_MSG(test,
!memchr_inv(page_dst + PAGE_SIZE, 0xA5, PAGE_SIZE),
"copy_page overflow into adjacent page");
This also lets you delete page_zero[] entirely, which on
PAGE_SIZE=64K configs (arm64) saves a non-trivial amount of BSS.
> +}
> +
> +static void copy_page_test(struct kunit *test)
> +{
> + init_page(test);
> +
> + /* Copy. */
> + copy_page(page_dst, page_src);
> +
> + /* Verify byte-for-byte exact. */
> + KUNIT_ASSERT_EQ_MSG(test,
> + memcmp(page_dst, page_src, PAGE_SIZE), 0,
> + "copy_page content mismatch with random data");
> +
> + /* Verify no overflow into second page. */
> + KUNIT_ASSERT_EQ_MSG(test,
> + memcmp(page_dst + PAGE_SIZE, page_zero, PAGE_SIZE), 0,
> + "copy_page overflow into adjacent page");
> +}
> +
> +#ifdef CONFIG_ARCH_HAS_COPY_MC
> +static void copy_mc_page_test(struct kunit *test)
> +{
> + int ret;
> +
> + init_page(test);
> +
> + /* Copy and check return value. */
> + ret = copy_mc_page(page_dst, page_src);
From sashiko:
Does this introduce a build regression on architectures like x86_64 or
powerpc?
The CONFIG_ARCH_HAS_COPY_MC flag is selected by multiple architectures,
but copy_mc_page() is an arm64-specific API. Other architectures use the
generic copy_mc_to_kernel() API instead.
If the kernel is built with KUnit enabled on non-arm64 architectures, it
appears copy_mc_page() would be an undeclared identifier.
Thanks.
Shuai
next prev parent reply other threads:[~2026-05-27 13:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-18 8:49 [PATCH v14 0/8] arm64: add ARCH_HAS_COPY_MC support Ruidong Tian
2026-05-18 8:49 ` [PATCH v14 1/8] uaccess: add generic fallback version of copy_mc_to_user() Ruidong Tian
2026-05-27 9:16 ` Shuai Xue
2026-05-18 8:49 ` [PATCH v14 2/8] ACPI: APEI: GHES: use exception context to gate SIGBUS on poison consumption Ruidong Tian
2026-05-27 9:34 ` Shuai Xue
2026-05-18 8:49 ` [PATCH v14 3/8] arm64: add support for ARCH_HAS_COPY_MC Ruidong Tian
2026-05-27 11:35 ` Shuai Xue
2026-06-04 8:10 ` Ruidong Tian
2026-05-18 8:49 ` [PATCH v14 4/8] mm/hwpoison: return -EFAULT when copy fail in copy_mc_[user]_highpage() Ruidong Tian
2026-05-27 11:44 ` Shuai Xue
2026-05-18 8:49 ` [PATCH v14 5/8] arm64: support copy_mc_[user]_highpage() Ruidong Tian
2026-05-27 12:11 ` Shuai Xue
2026-05-18 8:49 ` [PATCH v14 6/8] lib/test: memcpy_kunit: add copy_page() and copy_mc_page() tests Ruidong Tian
2026-05-27 13:43 ` Shuai Xue [this message]
2026-05-18 8:49 ` [PATCH v14 7/8] arm64: introduce copy_mc_to_kernel() implementation Ruidong Tian
2026-05-28 3:10 ` Shuai Xue
2026-05-18 8:49 ` [PATCH v14 8/8] lib/tests: memcpy_kunit: add memcpy_mc() and memcpy_mc_large() test Ruidong Tian
2026-05-28 3:17 ` Shuai Xue
2026-05-18 15:05 ` [PATCH v14 0/8] arm64: add ARCH_HAS_COPY_MC support Kefeng Wang
2026-06-05 7:33 ` Ruidong Tian
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