From patchwork Tue Aug 22 01:54:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joel Fernandes X-Patchwork-Id: 13360070 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 339DFEE49AA for ; Tue, 22 Aug 2023 01:55:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232193AbjHVBzt (ORCPT ); Mon, 21 Aug 2023 21:55:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232195AbjHVBzq (ORCPT ); Mon, 21 Aug 2023 21:55:46 -0400 Received: from mail-il1-x131.google.com (mail-il1-x131.google.com [IPv6:2607:f8b0:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2649A194 for ; Mon, 21 Aug 2023 18:55:27 -0700 (PDT) Received: by mail-il1-x131.google.com with SMTP id e9e14a558f8ab-34ca63f6a27so6271005ab.1 for ; Mon, 21 Aug 2023 18:55:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; t=1692669326; x=1693274126; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=FD9aGvqokkyzhhNkz6Ym1Row+eZXw3mkXyW6dIKtxjg=; b=BVxKaBwCWqmv9ynuQE7s7YtVK38FkX779KlBkPDkQBjoFlq8GAIqxdpbPgdXIHuYEP sTZl8JURdoNTsMC+vviGXqt9EnyyK4mtdmmYuLB06JdlbsUAxre1uPUPQ9095aYWBBzQ UX41cyoBUmNRAXgSpAygarUMAnDMlAVDQL8Lk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692669326; x=1693274126; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FD9aGvqokkyzhhNkz6Ym1Row+eZXw3mkXyW6dIKtxjg=; b=VtI9bLyqikS0s6RqZKJh2I2jVAHA2iBcqGOZpomt/ECMXCTv35oxXm0or48f8zzSHc HU5GXHHHym2xsNmeIkPuS1leCnAXtgb1oylBVT5qBQn1eaLLduc8cs+T2bAbPr+y+BYX Yloi5LX2cACE7JIGBvQCVcajXLchS2M7CYmXUMNPXwzDNJ4KDOBRg8Ss7hpQl5Zr2BP3 FSERA/5ckQ4zBVWoQOl2xgIOPX//LJyZ/6dsLmbN7kA3usyEcEP1eP2BemNRv9+MMOEm 9RYi/STtPOaPt+9u0f+GwNcyg17t6Yz5w+rPThsnqInqspwwc9hiPgipmVFsJ+tiVx32 M5tQ== X-Gm-Message-State: AOJu0YyG8iNGb9Y7Vac0AXHZ/3gP4MLBnyjdJIbrpaLaQ8YDtiGdRCXz tF6MSCndSETL/L50/UeO1D8nuw== X-Google-Smtp-Source: AGHT+IHvcEbCoDqCw1Fy8RgEWPuit/xENlfoh2EHuYOQYRSjxZ82L50BdV84tK7DyIjYWJTuRfLE/Q== X-Received: by 2002:a05:6e02:190d:b0:346:1185:31d0 with SMTP id w13-20020a056e02190d00b00346118531d0mr11455463ilu.9.1692669326463; Mon, 21 Aug 2023 18:55:26 -0700 (PDT) Received: from joelboxx5.c.googlers.com.com (156.190.123.34.bc.googleusercontent.com. [34.123.190.156]) by smtp.gmail.com with ESMTPSA id q11-20020a92d40b000000b0034886587bdcsm2907390ilm.18.2023.08.21.18.55.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Aug 2023 18:55:25 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Shuah Khan , Vlastimil Babka , Michal Hocko , Linus Torvalds , Lorenzo Stoakes , Kirill A Shutemov , "Liam R. Howlett" , "Paul E. McKenney" , Suren Baghdasaryan , Kalesh Singh , Lokesh Gidra Subject: [PATCH v5 6/7] selftests: mm: Add a test for remapping within a range Date: Tue, 22 Aug 2023 01:54:59 +0000 Message-ID: <20230822015501.791637-7-joel@joelfernandes.org> X-Mailer: git-send-email 2.42.0.rc1.204.g551eb34607-goog In-Reply-To: <20230822015501.791637-1-joel@joelfernandes.org> References: <20230822015501.791637-1-joel@joelfernandes.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Move a block of memory within a memory range. Any alignment optimization on the source address may cause corruption. Verify using kselftest that it works. I have also verified with tracing that such optimization does not happen due to this check in can_align_down(): if (!for_stack && vma->vm_start <= addr_masked) return false; Signed-off-by: Joel Fernandes (Google) Reviewed-by: Lorenzo Stoakes --- tools/testing/selftests/mm/mremap_test.c | 79 +++++++++++++++++++++++- 1 file changed, 78 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c index d7366074e2a8..f45d1abedc9c 100644 --- a/tools/testing/selftests/mm/mremap_test.c +++ b/tools/testing/selftests/mm/mremap_test.c @@ -23,6 +23,7 @@ #define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */ #define MIN(X, Y) ((X) < (Y) ? (X) : (Y)) +#define SIZE_MB(m) ((size_t)m * (1024 * 1024)) struct config { unsigned long long src_alignment; @@ -226,6 +227,79 @@ static void mremap_expand_merge_offset(FILE *maps_fp, unsigned long page_size) ksft_test_result_fail("%s\n", test_name); } +/* + * Verify that an mremap within a range does not cause corruption + * of unrelated part of range. + * + * Consider the following range which is 2MB aligned and is + * a part of a larger 10MB range which is not shown. Each + * character is 256KB below making the source and destination + * 2MB each. The lower case letters are moved (s to d) and the + * upper case letters are not moved. The below test verifies + * that the upper case S letters are not corrupted by the + * adjacent mremap. + * + * |DDDDddddSSSSssss| + */ +static void mremap_move_within_range(char pattern_seed) +{ + char *test_name = "mremap mremap move within range"; + void *src, *dest; + int i, success = 1; + + size_t size = SIZE_MB(20); + void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (ptr == MAP_FAILED) { + perror("mmap"); + success = 0; + goto out; + } + memset(ptr, 0, size); + + src = ptr + SIZE_MB(6); + src = (void *)((unsigned long)src & ~(SIZE_MB(2) - 1)); + + /* Set byte pattern for source block. */ + srand(pattern_seed); + for (i = 0; i < SIZE_MB(2); i++) { + ((char *)src)[i] = (char) rand(); + } + + dest = src - SIZE_MB(2); + + void *new_ptr = mremap(src + SIZE_MB(1), SIZE_MB(1), SIZE_MB(1), + MREMAP_MAYMOVE | MREMAP_FIXED, dest + SIZE_MB(1)); + if (new_ptr == MAP_FAILED) { + perror("mremap"); + success = 0; + goto out; + } + + /* Verify byte pattern after remapping */ + srand(pattern_seed); + for (i = 0; i < SIZE_MB(1); i++) { + char c = (char) rand(); + + if (((char *)src)[i] != c) { + ksft_print_msg("Data at src at %d got corrupted due to unrelated mremap\n", + i); + ksft_print_msg("Expected: %#x\t Got: %#x\n", c & 0xff, + ((char *) src)[i] & 0xff); + success = 0; + } + } + +out: + if (munmap(ptr, size) == -1) + perror("munmap"); + + if (success) + ksft_test_result_pass("%s\n", test_name); + else + ksft_test_result_fail("%s\n", test_name); +} + /* * Returns the start address of the mapping on success, else returns * NULL on failure. @@ -491,6 +565,7 @@ int main(int argc, char **argv) unsigned int threshold_mb = VALIDATION_DEFAULT_THRESHOLD; unsigned int pattern_seed; int num_expand_tests = 2; + int num_misc_tests = 1; struct test test_cases[MAX_TEST] = {}; struct test perf_test_cases[MAX_PERF_TEST]; int page_size; @@ -572,7 +647,7 @@ int main(int argc, char **argv) (threshold_mb * _1MB >= _1GB); ksft_set_plan(ARRAY_SIZE(test_cases) + (run_perf_tests ? - ARRAY_SIZE(perf_test_cases) : 0) + num_expand_tests); + ARRAY_SIZE(perf_test_cases) : 0) + num_expand_tests + num_misc_tests); for (i = 0; i < ARRAY_SIZE(test_cases); i++) run_mremap_test_case(test_cases[i], &failures, threshold_mb, @@ -590,6 +665,8 @@ int main(int argc, char **argv) fclose(maps_fp); + mremap_move_within_range(pattern_seed); + if (run_perf_tests) { ksft_print_msg("\n%s\n", "mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:");