mremap_test uses a random data stream to detect corruption after remap operations. This requires seed handling and byte by byte validation, which is inefficient.
Replace it with a deterministic pattern where every word in a page contains its one-based page index. Use memcpy() and memcmp() to initialize and validate the mappings. Remove the pattern seed and update the comment diagrams to reflect the new deterministic pattern. Suggested-by: David Hildenbrand (Arm) <[email protected]> Signed-off-by: Sarthak Sharma <[email protected]> --- tools/testing/selftests/mm/mremap_test.c | 220 +++++++++-------------- 1 file changed, 85 insertions(+), 135 deletions(-) diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c index 955727607d4f..92ffcbe547b5 100644 --- a/tools/testing/selftests/mm/mremap_test.c +++ b/tools/testing/selftests/mm/mremap_test.c @@ -13,8 +13,8 @@ #include <sys/ioctl.h> #include <sys/mman.h> #include <syscall.h> -#include <time.h> #include <stdbool.h> +#include <stdint.h> #include "kselftest.h" @@ -304,11 +304,11 @@ static void mremap_expand_merge_offset(FILE *maps_fp, unsigned long page_size) * * |DDDDddddSSSSssss| */ -static void mremap_move_within_range(unsigned int pattern_seed, char *rand_addr) +static void mremap_move_within_range(char *pattern_addr) { char *test_name = "mremap move within range"; void *src, *dest; - unsigned int i, success = 1; + unsigned int success = 1; size_t size = SIZE_MB(20); void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE, @@ -324,7 +324,7 @@ static void mremap_move_within_range(unsigned int pattern_seed, char *rand_addr) src = (void *)((unsigned long)src & ~(SIZE_MB(2) - 1)); /* Set byte pattern for source block. */ - memcpy(src, rand_addr, SIZE_MB(2)); + memcpy(src, pattern_addr + SIZE_MB(2), SIZE_MB(2)); dest = src - SIZE_MB(2); @@ -337,17 +337,9 @@ static void mremap_move_within_range(unsigned int pattern_seed, char *rand_addr) } /* 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; - } + if (memcmp(src, pattern_addr + SIZE_MB(2), SIZE_MB(1))) { + ksft_print_msg("Source data was corrupted\n"); + success = 0; } out_unmap: @@ -356,32 +348,24 @@ static void mremap_move_within_range(unsigned int pattern_seed, char *rand_addr) ksft_test_result(success, "%s\n", test_name); } -static bool is_multiple_vma_range_ok(unsigned int pattern_seed, - char *ptr, unsigned long page_size) +static bool is_multiple_vma_range_ok(char *pattern_addr, char *ptr, + unsigned long page_size) { - int i; - - srand(pattern_seed); - for (i = 0; i <= 10; i += 2) { - int j; - char *buf = &ptr[i * page_size]; + for (int i = 0; i <= 10; i += 2) { size_t size = i == 4 ? 2 * page_size : page_size; - for (j = 0; j < size; j++) { - char chr = rand(); - - if (chr != buf[j]) { - ksft_print_msg("page %d offset %d corrupted, expected %d got %d\n", - i, j, chr, buf[j]); - return false; - } + if (memcmp(ptr + i * page_size, pattern_addr + i * page_size, + size)) { + ksft_print_msg("Data in VMA starting at page %d got corrupted\n", + i); + return false; } } return true; } -static void mremap_move_multiple_vmas(unsigned int pattern_seed, +static void mremap_move_multiple_vmas(char *pattern_addr, unsigned long page_size, bool dont_unmap) { @@ -416,13 +400,15 @@ static void mremap_move_multiple_vmas(unsigned int pattern_seed, goto out_unmap; } + memcpy(ptr, pattern_addr, size); + /* * Unmap so we end up with: * * 0 2 4 5 6 8 10 offset in buffer * |*| |*| |*****| |*| |*| * |*| |*| |*****| |*| |*| - * 0 1 2 3 4 5 6 pattern offset + * 0 2 4 5 6 8 10 pattern offset */ for (i = 1; i < 10; i += 2) { if (i == 5) @@ -435,18 +421,6 @@ static void mremap_move_multiple_vmas(unsigned int pattern_seed, } } - srand(pattern_seed); - - /* Set up random patterns. */ - for (i = 0; i <= 10; i += 2) { - int j; - size_t size = i == 4 ? 2 * page_size : page_size; - char *buf = &ptr[i * page_size]; - - for (j = 0; j < size; j++) - buf[j] = rand(); - } - /* First, just move the whole thing. */ if (mremap(ptr, size, size, mremap_flags, tgt_ptr) == MAP_FAILED) { ksft_perror("mremap"); @@ -454,7 +428,7 @@ static void mremap_move_multiple_vmas(unsigned int pattern_seed, goto out_unmap; } /* Check move was ok. */ - if (!is_multiple_vma_range_ok(pattern_seed, tgt_ptr, page_size)) { + if (!is_multiple_vma_range_ok(pattern_addr, tgt_ptr, page_size)) { success = false; goto out_unmap; } @@ -467,7 +441,7 @@ static void mremap_move_multiple_vmas(unsigned int pattern_seed, goto out_unmap; } /* Check that the move is ok. */ - if (!is_multiple_vma_range_ok(pattern_seed, &tgt_ptr[size], page_size)) { + if (!is_multiple_vma_range_ok(pattern_addr, &tgt_ptr[size], page_size)) { success = false; goto out_unmap; } @@ -487,7 +461,7 @@ static void mremap_move_multiple_vmas(unsigned int pattern_seed, goto out_unmap; } /* Check that the move is ok. */ - if (!is_multiple_vma_range_ok(pattern_seed, tgt_ptr, page_size)) { + if (!is_multiple_vma_range_ok(pattern_addr, tgt_ptr, page_size)) { success = false; goto out_unmap; } @@ -573,7 +547,7 @@ static void mremap_shrink_multiple_vmas(unsigned long page_size, ksft_test_result(success, "%s%s\n", test_name, inplace ? " [inplace]" : ""); } -static void mremap_move_multiple_vmas_split(unsigned int pattern_seed, +static void mremap_move_multiple_vmas_split(char *pattern_addr, unsigned long page_size, bool dont_unmap) { @@ -608,13 +582,15 @@ static void mremap_move_multiple_vmas_split(unsigned int pattern_seed, goto out_unmap; } + memcpy(ptr, pattern_addr, size); + /* * Unmap so we end up with: * * 0 1 2 3 4 5 6 7 8 9 10 offset in buffer * |**********| |*******| * |**********| |*******| - * 0 1 2 3 4 5 6 7 8 9 pattern offset + * 0 1 2 3 4 5 6 7 8 9 10 pattern offset */ if (munmap(&ptr[5 * page_size], page_size)) { ksft_perror("munmap"); @@ -622,19 +598,6 @@ static void mremap_move_multiple_vmas_split(unsigned int pattern_seed, goto out_unmap; } - /* Set up random patterns. */ - srand(pattern_seed); - for (i = 0; i < 10; i++) { - int j; - char *buf = &ptr[i * page_size]; - - if (i == 5) - continue; - - for (j = 0; j < page_size; j++) - buf[j] = rand(); - } - /* * Move the below: * @@ -642,14 +605,14 @@ static void mremap_move_multiple_vmas_split(unsigned int pattern_seed, * 0 1 2 3 4 5 6 7 8 9 10 offset in buffer * |**********| |*******| * |**********| |*******| - * 0 1 2 3 4 5 6 7 8 9 pattern offset + * 0 1 2 3 4 5 6 7 8 9 10 pattern offset * * Into: * * 0 1 2 3 4 5 6 7 offset in buffer * |*****| |*****| * |*****| |*****| - * 2 3 4 5 6 7 pattern offset + * 2 3 4 5 6 7 8 9 pattern offset */ if (mremap(&ptr[2 * page_size], size - 3 * page_size, size - 3 * page_size, mremap_flags, tgt_ptr) == MAP_FAILED) { @@ -658,28 +621,16 @@ static void mremap_move_multiple_vmas_split(unsigned int pattern_seed, goto out_unmap; } - /* Offset into random pattern. */ - srand(pattern_seed); - for (i = 0; i < 2 * page_size; i++) - rand(); - /* Check pattern. */ for (i = 0; i < 7; i++) { - int j; - char *buf = &tgt_ptr[i * page_size]; - if (i == 3) continue; - for (j = 0; j < page_size; j++) { - char chr = rand(); - - if (chr != buf[j]) { - ksft_print_msg("page %d offset %d corrupted, expected %d got %d\n", - i, j, chr, buf[j]); - success = false; - goto out_unmap; - } + if (memcmp(tgt_ptr + i * page_size, + pattern_addr + (i + 2) * page_size, page_size)) { + ksft_print_msg("Data in page %d got corrupted\n", i + 2); + success = false; + goto out_unmap; } } @@ -958,11 +909,12 @@ static bool validate_test_data(char *addr, size_t size, char *pattern_addr, !memcmp(addr + end, pattern_addr + 2 * len, len); } -static int remap_region(struct config c, char *rand_addr, size_t rand_size, +static int remap_region(struct config c, char *pattern_addr, size_t pattern_size, size_t page_size) { void *addr, *tmp_addr, *src_addr, *dest_addr, *dest_preamble_addr = NULL; long long align_mask, offset; + char *preamble_pattern = NULL; int ret = 0; src_addr = get_source_mapping(c); @@ -972,7 +924,8 @@ static int remap_region(struct config c, char *rand_addr, size_t rand_size, } /* Set byte pattern for source block. */ - populate_test_data(src_addr, c.region_size, rand_addr, rand_size, page_size); + populate_test_data(src_addr, c.region_size, pattern_addr, + pattern_size, page_size); /* Mask to zero out lower bits of address for alignment */ align_mask = ~(c.dest_alignment - 1); @@ -1012,8 +965,9 @@ static int remap_region(struct config c, char *rand_addr, size_t rand_size, goto clean_up_src; } + preamble_pattern = pattern_addr + pattern_size - c.dest_preamble_size; /* Set byte pattern for the dest preamble block. */ - memcpy(dest_preamble_addr, rand_addr, c.dest_preamble_size); + memcpy(dest_preamble_addr, preamble_pattern, c.dest_preamble_size); } dest_addr = mremap(src_addr, c.region_size, c.region_size, @@ -1026,8 +980,8 @@ static int remap_region(struct config c, char *rand_addr, size_t rand_size, } /* Verify byte pattern after remapping */ - if (!validate_test_data(dest_addr, c.region_size, rand_addr, - rand_size, page_size)) { + if (!validate_test_data(dest_addr, c.region_size, pattern_addr, + pattern_size, page_size)) { ksft_print_msg("Data after remap doesn't match\n"); ret = -1; goto clean_up_dest; @@ -1035,7 +989,7 @@ static int remap_region(struct config c, char *rand_addr, size_t rand_size, /* Verify the dest preamble byte pattern after remapping */ if (c.dest_preamble_size && - memcmp(dest_preamble_addr, rand_addr, c.dest_preamble_size)) { + memcmp(dest_preamble_addr, preamble_pattern, c.dest_preamble_size)) { ksft_print_msg("Preamble data after remap doesn't match\n"); ret = -1; goto clean_up_dest; @@ -1057,12 +1011,11 @@ static int remap_region(struct config c, char *rand_addr, size_t rand_size, * the beginning of the mapping just because the aligned * down address landed on a mapping that maybe does not exist. */ -static void mremap_move_1mb_from_start(unsigned int pattern_seed, - char *rand_addr) +static void mremap_move_1mb_from_start(char *pattern_addr) { char *test_name = "mremap move 1mb from start at 1MB+256KB aligned src"; void *src = NULL, *dest = NULL; - unsigned int i, success = 1; + unsigned int success = 1; /* Config to reuse get_source_mapping() to do an aligned mmap. */ struct config c = { @@ -1084,7 +1037,7 @@ static void mremap_move_1mb_from_start(unsigned int pattern_seed, } /* Set byte pattern for source block. */ - memcpy(src, rand_addr, SIZE_MB(2)); + memcpy(src, pattern_addr, SIZE_MB(2)); /* * Unmap the beginning of dest so that the aligned address @@ -1101,17 +1054,9 @@ static void mremap_move_1mb_from_start(unsigned int pattern_seed, } /* 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; - } + if (memcmp(src, pattern_addr, SIZE_MB(1))) { + ksft_print_msg("Data before the remapped range was corrupted\n"); + success = 0; } out: @@ -1125,11 +1070,11 @@ static void mremap_move_1mb_from_start(unsigned int pattern_seed, } static void run_mremap_test_case(struct test test_case, - char *rand_addr, - size_t rand_size, + char *pattern_addr, + size_t pattern_size, size_t page_size) { - int ret = remap_region(test_case.config, rand_addr, rand_size, page_size); + int ret = remap_region(test_case.config, pattern_addr, pattern_size, page_size); if (ret < 0) { if (test_case.expect_failure) @@ -1146,47 +1091,52 @@ static void run_mremap_test_case(struct test test_case, } } +static void fill_pattern(char *pattern_addr, size_t pattern_size, size_t page_size) +{ + size_t nr_pages = pattern_size / page_size; + size_t words_per_page = page_size / sizeof(uint32_t); + size_t page, word; + + for (page = 0; page < nr_pages; page++) { + uint32_t *page_addr = (uint32_t *)pattern_addr + page * words_per_page; + uint32_t val = page + 1; + + for (word = 0; word < words_per_page; word++) + page_addr[word] = val; + } +} + #define MAX_TEST 15 int main(void) { unsigned int i; - unsigned int pattern_seed; - char *rand_addr; - size_t rand_size; + char *pattern_addr; + size_t pattern_size; int num_expand_tests = 2; int num_misc_tests = 9; struct test test_cases[MAX_TEST] = {}; int page_size; - time_t t; FILE *maps_fp; ksft_print_header(); get_mmap_min_addr(); - pattern_seed = (unsigned int) time(&t); - - ksft_print_msg("Test configs:\n"); - ksft_print_msg("pattern_seed=%u\n", pattern_seed); - /* - * The 40MB destination preamble determines the random buffer size + * The 40MB destination preamble determines the pattern buffer size */ - rand_size = 10 * _4MB; + pattern_size = 10 * _4MB; - rand_addr = (char *)mmap(NULL, rand_size, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if (rand_addr == MAP_FAILED) - ksft_exit_fail_perror("cannot mmap rand_addr"); - - /* fill stream of random bytes */ - srand(pattern_seed); - for (unsigned long i = 0; i < rand_size; ++i) - rand_addr[i] = (char) rand(); + pattern_addr = (char *)mmap(NULL, pattern_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (pattern_addr == MAP_FAILED) + ksft_exit_fail_perror("cannot mmap pattern_addr"); page_size = sysconf(_SC_PAGESIZE); + fill_pattern(pattern_addr, pattern_size, page_size); + /* Expected mremap failures */ test_cases[0] = MAKE_TEST(page_size, page_size, page_size, OVERLAPPING, EXPECT_FAILURE, @@ -1240,31 +1190,31 @@ int main(void) ksft_set_plan(ARRAY_SIZE(test_cases) + num_expand_tests + num_misc_tests); for (i = 0; i < ARRAY_SIZE(test_cases); i++) - run_mremap_test_case(test_cases[i], rand_addr, rand_size, page_size); + run_mremap_test_case(test_cases[i], pattern_addr, pattern_size, page_size); maps_fp = fopen("/proc/self/maps", "r"); if (maps_fp == NULL) { - munmap(rand_addr, rand_size); + munmap(pattern_addr, pattern_size); ksft_exit_fail_msg("Failed to read /proc/self/maps: %s\n", strerror(errno)); } mremap_expand_merge(maps_fp, page_size); mremap_expand_merge_offset(maps_fp, page_size); - mremap_move_within_range(pattern_seed, rand_addr); - mremap_move_1mb_from_start(pattern_seed, rand_addr); + mremap_move_within_range(pattern_addr); + mremap_move_1mb_from_start(pattern_addr); mremap_shrink_multiple_vmas(page_size, /* inplace= */true); mremap_shrink_multiple_vmas(page_size, /* inplace= */false); - mremap_move_multiple_vmas(pattern_seed, page_size, /* dontunmap= */ false); - mremap_move_multiple_vmas(pattern_seed, page_size, /* dontunmap= */ true); - mremap_move_multiple_vmas_split(pattern_seed, page_size, /* dontunmap= */ false); - mremap_move_multiple_vmas_split(pattern_seed, page_size, /* dontunmap= */ true); + mremap_move_multiple_vmas(pattern_addr, page_size, /* dontunmap= */ false); + mremap_move_multiple_vmas(pattern_addr, page_size, /* dontunmap= */ true); + mremap_move_multiple_vmas_split(pattern_addr, page_size, /* dontunmap= */ false); + mremap_move_multiple_vmas_split(pattern_addr, page_size, /* dontunmap= */ true); mremap_move_multi_invalid_vmas(maps_fp, page_size); fclose(maps_fp); - munmap(rand_addr, rand_size); + munmap(pattern_addr, pattern_size); ksft_finished(); } -- 2.53.0
