From: Christoph Hellwig Date: Mon, 18 May 2026 05:18:01 +0000 (+0200) Subject: raid6_kunit: randomize buffer alignment X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8cf0a6c4bb9e09a2d280376dba723b218c139e58;p=thirdparty%2Fkernel%2Flinux.git raid6_kunit: randomize buffer alignment Add code to add random alignment to the buffers to test the case where they are not page aligned, and to move the buffers to the end of the allocation so that they are next to the vmalloc guard page. This does not include the recovery buffers as the recovery requires page alignment. Link: https://lore.kernel.org/20260518051804.462141-19-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Ard Biesheuvel Tested-by: Ard Biesheuvel # kunit only on arm64 Cc: Albert Ou Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Arnd Bergmann Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Chris Mason Cc: Christian Borntraeger Cc: Dan Williams Cc: David Sterba Cc: Heiko Carstens Cc: Herbert Xu Cc: "H. Peter Anvin" Cc: Huacai Chen Cc: Ingo Molnar Cc: Li Nan Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Song Liu Cc: Sven Schnelle Cc: Vasily Gorbik Cc: WANG Xuerui Cc: Will Deacon Signed-off-by: Andrew Morton --- diff --git a/lib/raid/raid6/tests/raid6_kunit.c b/lib/raid/raid6/tests/raid6_kunit.c index 71adf8932e93..9f3e671a1224 100644 --- a/lib/raid/raid6/tests/raid6_kunit.c +++ b/lib/raid/raid6/tests/raid6_kunit.c @@ -21,6 +21,7 @@ MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING"); static struct rnd_state rng; static void *test_buffers[RAID6_KUNIT_MAX_BUFFERS]; +static void *aligned_buffers[RAID6_KUNIT_MAX_BUFFERS]; static void *test_recov_buffers[RAID6_KUNIT_MAX_FAILURES]; static size_t test_buflen; @@ -50,6 +51,14 @@ static unsigned int random_nr_buffers(void) RAID6_MIN_DISKS; } +/* Generate a random alignment that is a multiple of 64. */ +static unsigned int random_alignment(unsigned int max_alignment) +{ + if (max_alignment == 0) + return 0; + return (rand32() % (max_alignment + 1)) & ~63; +} + static void makedata(int start, int stop) { int i; @@ -80,7 +89,7 @@ static void test_recover_one(struct kunit *test, unsigned int nr_buffers, for (i = 0; i < RAID6_KUNIT_MAX_FAILURES; i++) memset(test_recov_buffers[i], 0xf0, test_buflen); - memcpy(dataptrs, test_buffers, sizeof(dataptrs)); + memcpy(dataptrs, aligned_buffers, sizeof(dataptrs)); dataptrs[faila] = test_recov_buffers[0]; dataptrs[failb] = test_recov_buffers[1]; @@ -102,13 +111,13 @@ static void test_recover_one(struct kunit *test, unsigned int nr_buffers, ta->recov->data2(nr_buffers, len, faila, failb, dataptrs); } - KUNIT_EXPECT_MEMEQ_MSG(test, test_buffers[faila], test_recov_buffers[0], + KUNIT_EXPECT_MEMEQ_MSG(test, aligned_buffers[faila], dataptrs[faila], len, "faila miscompared: %3d[%c] buffers %u len %u (failb=%3d[%c])\n", faila, member_type(nr_buffers, faila), nr_buffers, len, failb, member_type(nr_buffers, failb)); - KUNIT_EXPECT_MEMEQ_MSG(test, test_buffers[failb], test_recov_buffers[1], + KUNIT_EXPECT_MEMEQ_MSG(test, aligned_buffers[failb], dataptrs[failb], len, "failb miscompared: %3d[%c] buffers %u len %u (faila=%3d[%c])\n", failb, member_type(nr_buffers, failb), @@ -152,9 +161,9 @@ static void test_rmw_one(struct kunit *test, unsigned int nr_buffers, { const struct test_args *ta = test->param_value; - ta->gen->xor_syndrome(nr_buffers, p1, p2, len, test_buffers); + ta->gen->xor_syndrome(nr_buffers, p1, p2, len, aligned_buffers); makedata(p1, p2); - ta->gen->xor_syndrome(nr_buffers, p1, p2, len, test_buffers); + ta->gen->xor_syndrome(nr_buffers, p1, p2, len, aligned_buffers); test_recover(test, nr_buffers, len); } @@ -178,13 +187,33 @@ static void raid6_test_one(struct kunit *test) const struct test_args *ta = test->param_value; unsigned int nr_buffers = random_nr_buffers(); unsigned int len = random_length(RAID6_KUNIT_MAX_BYTES); + unsigned int max_alignment; + int i; /* Nuke syndromes */ memset(test_buffers[nr_buffers - 2], 0xee, test_buflen); memset(test_buffers[nr_buffers - 1], 0xee, test_buflen); + /* + * If we're not using the entire buffer size, inject randomize alignment + * into the buffer. + */ + max_alignment = RAID6_KUNIT_MAX_BYTES - len; + if (rand32() % 2 == 0) { + /* Use random alignments mod 64 */ + for (i = 0; i < nr_buffers; i++) + aligned_buffers[i] = test_buffers[i] + + random_alignment(max_alignment); + } else { + /* Go up to the guard page, to catch buffer overreads */ + unsigned int align = test_buflen - len; + + for (i = 0; i < nr_buffers; i++) + aligned_buffers[i] = test_buffers[i] + align; + } + /* Generate assumed good syndrome */ - ta->gen->gen_syndrome(nr_buffers, len, test_buffers); + ta->gen->gen_syndrome(nr_buffers, len, aligned_buffers); test_recover(test, nr_buffers, len);