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 8/8] lib/tests: memcpy_kunit: add memcpy_mc() and memcpy_mc_large() test
Date: Thu, 28 May 2026 11:17:17 +0800 [thread overview]
Message-ID: <2e413153-c9e7-41dc-ad8e-522871381bf7@linux.alibaba.com> (raw)
In-Reply-To: <20260518084956.2538442-9-tianruidong@linux.alibaba.com>
On 5/18/26 4:49 PM, Ruidong Tian wrote:
> memcpy_mc() is the Machine-Check safe memcpy variant that returns the
> number of bytes NOT copied on a hardware memory error, or 0 on success.
>
> Add two test cases modeled after the existing memcpy_test() and
> memcpy_large_test() implementations:
Same build issue as with copy_mc_page_test: memcpy_mc() is an arm64-
only symbol.
1. Cross-architecture build break (BLOCKER, same as patch 6)
These tests are gated on CONFIG_ARCH_HAS_COPY_MC, which is also
selected by x86_64 and ppc64. Neither architecture provides a
memcpy_mc() symbol -- they use copy_mc_to_kernel() directly.
On x86_64:
lib/tests/memcpy_kunit.c: error: implicit declaration of
function 'memcpy_mc' [-Werror=implicit-function-declaration]
Fix: guard with __HAVE_ARCH_MEMCPY_MC instead:
#ifdef __HAVE_ARCH_MEMCPY_MC
static void memcpy_mc_test(...) { ... }
static void memcpy_mc_large_test(...) { ... }
#endif
>
> Signed-off-by: Ruidong Tian <tianruidong@linux•alibaba.com>
> ---
> lib/tests/memcpy_kunit.c | 113 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 112 insertions(+), 1 deletion(-)
>
> diff --git a/lib/tests/memcpy_kunit.c b/lib/tests/memcpy_kunit.c
> index 85df53ccfb0c..b4b2dafb50f1 100644
> --- a/lib/tests/memcpy_kunit.c
> +++ b/lib/tests/memcpy_kunit.c
> @@ -552,6 +552,115 @@ static void copy_mc_page_test(struct kunit *test)
> memcmp(page_dst + PAGE_SIZE, page_zero, PAGE_SIZE), 0,
> "copy_mc_page overflow into adjacent page");
> }
> +/*
> + * memcpy_mc() is a Machine-Check safe memcpy variant.
> + * Signature: int memcpy_mc(void *dst, const void *src, size_t len)
> + * Returns: 0 on success, or number of bytes NOT copied on MC error.
> + *
> + * In the normal (no-poison) path it must behave identically to memcpy()
> + * and always return 0.
> + */
> +static void memcpy_mc_test(struct kunit *test)
> +{
> +#define TEST_OP "memcpy_mc"
> + struct some_bytes control = {
> + .data = { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + },
> + };
> + struct some_bytes zero = { };
> + struct some_bytes middle = {
> + .data = { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00,
> + 0x00, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + },
> + };
> + struct some_bytes three = {
> + .data = { 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
> + },
> + };
> + struct some_bytes dest = { };
> + int ret, count;
> + u8 *ptr;
> +
> + /* Verify static initializers. */
> + check(control, 0x20);
> + check(zero, 0);
> + compare("static initializers", dest, zero);
> +
> + /* Verify assignment. */
> + dest = control;
> + compare("direct assignment", dest, control);
> +
> + /* Verify complete overwrite. */
> + ret = memcpy_mc(dest.data, control.data, sizeof(dest.data));
> + KUNIT_ASSERT_EQ(test, ret, 0);
> + compare("complete overwrite", dest, control);
> +
> + /* Verify middle overwrite: 7 bytes at offset 12. */
> + dest = control;
> + ret = memcpy_mc(dest.data + 12, zero.data, 7);
> + KUNIT_ASSERT_EQ(test, ret, 0);
> + compare("middle overwrite", dest, middle);
> +
> + /* Verify zero-length copy is a no-op. */
> + dest = control;
> + ret = memcpy_mc(dest.data, zero.data, 0);
> + KUNIT_ASSERT_EQ(test, ret, 0);
> + compare("zero length", dest, control);
> +
> + /* Verify argument side-effects aren't repeated. */
> + dest = control;
> + ptr = dest.data;
> + count = 1;
> + memcpy(ptr++, zero.data, count++);
> + ptr += 8;
> + memcpy(ptr++, zero.data, count++);
This is a verbatim paste from memcpy_test(). The intent is to
verify that the memcpy_mc macro doesn't double-evaluate arguments,
but the test doesn't actually call memcpy_mc(). Please change the
two memcpy() calls to memcpy_mc() and assert their return values.
Thanks
Shuai
next prev parent reply other threads:[~2026-05-28 3:17 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
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 [this message]
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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