| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Test cases for SL[AOU]B/page initialization at alloc/free time. |
| */ |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/string.h> |
| #include <linux/vmalloc.h> |
| |
| #define GARBAGE_INT (0x09A7BA9E) |
| #define GARBAGE_BYTE (0x9E) |
| |
| #define REPORT_FAILURES_IN_FN() \ |
| do { \ |
| if (failures) \ |
| pr_info("%s failed %d out of %d times\n", \ |
| __func__, failures, num_tests); \ |
| else \ |
| pr_info("all %d tests in %s passed\n", \ |
| num_tests, __func__); \ |
| } while (0) |
| |
| /* Calculate the number of uninitialized bytes in the buffer. */ |
| static int __init count_nonzero_bytes(void *ptr, size_t size) |
| { |
| int i, ret = 0; |
| unsigned char *p = (unsigned char *)ptr; |
| |
| for (i = 0; i < size; i++) |
| if (p[i]) |
| ret++; |
| return ret; |
| } |
| |
| /* Fill a buffer with garbage, skipping |skip| first bytes. */ |
| static void __init fill_with_garbage_skip(void *ptr, int size, size_t skip) |
| { |
| unsigned int *p = (unsigned int *)((char *)ptr + skip); |
| int i = 0; |
| |
| WARN_ON(skip > size); |
| size -= skip; |
| |
| while (size >= sizeof(*p)) { |
| p[i] = GARBAGE_INT; |
| i++; |
| size -= sizeof(*p); |
| } |
| if (size) |
| memset(&p[i], GARBAGE_BYTE, size); |
| } |
| |
| static void __init fill_with_garbage(void *ptr, size_t size) |
| { |
| fill_with_garbage_skip(ptr, size, 0); |
| } |
| |
| static int __init do_alloc_pages_order(int order, int *total_failures) |
| { |
| struct page *page; |
| void *buf; |
| size_t size = PAGE_SIZE << order; |
| |
| page = alloc_pages(GFP_KERNEL, order); |
| if (!page) |
| goto err; |
| buf = page_address(page); |
| fill_with_garbage(buf, size); |
| __free_pages(page, order); |
| |
| page = alloc_pages(GFP_KERNEL, order); |
| if (!page) |
| goto err; |
| buf = page_address(page); |
| if (count_nonzero_bytes(buf, size)) |
| (*total_failures)++; |
| fill_with_garbage(buf, size); |
| __free_pages(page, order); |
| return 1; |
| err: |
| (*total_failures)++; |
| return 1; |
| } |
| |
| /* Test the page allocator by calling alloc_pages with different orders. */ |
| static int __init test_pages(int *total_failures) |
| { |
| int failures = 0, num_tests = 0; |
| int i; |
| |
| for (i = 0; i < NR_PAGE_ORDERS; i++) |
| num_tests += do_alloc_pages_order(i, &failures); |
| |
| REPORT_FAILURES_IN_FN(); |
| *total_failures += failures; |
| return num_tests; |
| } |
| |
| /* Test kmalloc() with given parameters. */ |
| static int __init do_kmalloc_size(size_t size, int *total_failures) |
| { |
| void *buf; |
| |
| buf = kmalloc(size, GFP_KERNEL); |
| if (!buf) |
| goto err; |
| fill_with_garbage(buf, size); |
| kfree(buf); |
| |
| buf = kmalloc(size, GFP_KERNEL); |
| if (!buf) |
| goto err; |
| if (count_nonzero_bytes(buf, size)) |
| (*total_failures)++; |
| fill_with_garbage(buf, size); |
| kfree(buf); |
| return 1; |
| err: |
| (*total_failures)++; |
| return 1; |
| } |
| |
| /* Test vmalloc() with given parameters. */ |
| static int __init do_vmalloc_size(size_t size, int *total_failures) |
| { |
| void *buf; |
| |
| buf = vmalloc(size); |
| if (!buf) |
| goto err; |
| fill_with_garbage(buf, size); |
| vfree(buf); |
| |
| buf = vmalloc(size); |
| if (!buf) |
| goto err; |
| if (count_nonzero_bytes(buf, size)) |
| (*total_failures)++; |
| fill_with_garbage(buf, size); |
| vfree(buf); |
| return 1; |
| err: |
| (*total_failures)++; |
| return 1; |
| } |
| |
| /* Test kmalloc()/vmalloc() by allocating objects of different sizes. */ |
| static int __init test_kvmalloc(int *total_failures) |
| { |
| int failures = 0, num_tests = 0; |
| int i, size; |
| |
| for (i = 0; i < 20; i++) { |
| size = 1 << i; |
| num_tests += do_kmalloc_size(size, &failures); |
| num_tests += do_vmalloc_size(size, &failures); |
| } |
| |
| REPORT_FAILURES_IN_FN(); |
| *total_failures += failures; |
| return num_tests; |
| } |
| |
| #define CTOR_BYTES (sizeof(unsigned int)) |
| #define CTOR_PATTERN (0x41414141) |
| /* Initialize the first 4 bytes of the object. */ |
| static void test_ctor(void *obj) |
| { |
| *(unsigned int *)obj = CTOR_PATTERN; |
| } |
| |
| /* |
| * Check the invariants for the buffer allocated from a slab cache. |
| * If the cache has a test constructor, the first 4 bytes of the object must |
| * always remain equal to CTOR_PATTERN. |
| * If the cache isn't an RCU-typesafe one, or if the allocation is done with |
| * __GFP_ZERO, then the object contents must be zeroed after allocation. |
| * If the cache is an RCU-typesafe one, the object contents must never be |
| * zeroed after the first use. This is checked by memcmp() in |
| * do_kmem_cache_size(). |
| */ |
| static bool __init check_buf(void *buf, int size, bool want_ctor, |
| bool want_rcu, bool want_zero) |
| { |
| int bytes; |
| bool fail = false; |
| |
| bytes = count_nonzero_bytes(buf, size); |
| WARN_ON(want_ctor && want_zero); |
| if (want_zero) |
| return bytes; |
| if (want_ctor) { |
| if (*(unsigned int *)buf != CTOR_PATTERN) |
| fail = 1; |
| } else { |
| if (bytes) |
| fail = !want_rcu; |
| } |
| return fail; |
| } |
| |
| #define BULK_SIZE 100 |
| static void *bulk_array[BULK_SIZE]; |
| |
| /* |
| * Test kmem_cache with given parameters: |
| * want_ctor - use a constructor; |
| * want_rcu - use SLAB_TYPESAFE_BY_RCU; |
| * want_zero - use __GFP_ZERO. |
| */ |
| static int __init do_kmem_cache_size(size_t size, bool want_ctor, |
| bool want_rcu, bool want_zero, |
| int *total_failures) |
| { |
| struct kmem_cache *c; |
| int iter; |
| bool fail = false; |
| gfp_t alloc_mask = GFP_KERNEL | (want_zero ? __GFP_ZERO : 0); |
| void *buf, *buf_copy; |
| |
| c = kmem_cache_create("test_cache", size, 1, |
| want_rcu ? SLAB_TYPESAFE_BY_RCU : 0, |
| want_ctor ? test_ctor : NULL); |
| for (iter = 0; iter < 10; iter++) { |
| /* Do a test of bulk allocations */ |
| if (!want_rcu && !want_ctor) { |
| int ret; |
| |
| ret = kmem_cache_alloc_bulk(c, alloc_mask, BULK_SIZE, bulk_array); |
| if (!ret) { |
| fail = true; |
| } else { |
| int i; |
| for (i = 0; i < ret; i++) |
| fail |= check_buf(bulk_array[i], size, want_ctor, want_rcu, want_zero); |
| kmem_cache_free_bulk(c, ret, bulk_array); |
| } |
| } |
| |
| buf = kmem_cache_alloc(c, alloc_mask); |
| /* Check that buf is zeroed, if it must be. */ |
| fail |= check_buf(buf, size, want_ctor, want_rcu, want_zero); |
| fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0); |
| |
| if (!want_rcu) { |
| kmem_cache_free(c, buf); |
| continue; |
| } |
| |
| /* |
| * If this is an RCU cache, use a critical section to ensure we |
| * can touch objects after they're freed. |
| */ |
| rcu_read_lock(); |
| /* |
| * Copy the buffer to check that it's not wiped on |
| * free(). |
| */ |
| buf_copy = kmalloc(size, GFP_ATOMIC); |
| if (buf_copy) |
| memcpy(buf_copy, buf, size); |
| |
| kmem_cache_free(c, buf); |
| /* |
| * Check that |buf| is intact after kmem_cache_free(). |
| * |want_zero| is false, because we wrote garbage to |
| * the buffer already. |
| */ |
| fail |= check_buf(buf, size, want_ctor, want_rcu, |
| false); |
| if (buf_copy) { |
| fail |= (bool)memcmp(buf, buf_copy, size); |
| kfree(buf_copy); |
| } |
| rcu_read_unlock(); |
| } |
| kmem_cache_destroy(c); |
| |
| *total_failures += fail; |
| return 1; |
| } |
| |
| /* |
| * Check that the data written to an RCU-allocated object survives |
| * reallocation. |
| */ |
| static int __init do_kmem_cache_rcu_persistent(int size, int *total_failures) |
| { |
| struct kmem_cache *c; |
| void *buf, *buf_contents, *saved_ptr; |
| void **used_objects; |
| int i, iter, maxiter = 1024; |
| bool fail = false; |
| |
| c = kmem_cache_create("test_cache", size, size, SLAB_TYPESAFE_BY_RCU, |
| NULL); |
| buf = kmem_cache_alloc(c, GFP_KERNEL); |
| if (!buf) |
| goto out; |
| saved_ptr = buf; |
| fill_with_garbage(buf, size); |
| buf_contents = kmalloc(size, GFP_KERNEL); |
| if (!buf_contents) { |
| kmem_cache_free(c, buf); |
| goto out; |
| } |
| used_objects = kmalloc_array(maxiter, sizeof(void *), GFP_KERNEL); |
| if (!used_objects) { |
| kmem_cache_free(c, buf); |
| kfree(buf_contents); |
| goto out; |
| } |
| memcpy(buf_contents, buf, size); |
| kmem_cache_free(c, buf); |
| /* |
| * Run for a fixed number of iterations. If we never hit saved_ptr, |
| * assume the test passes. |
| */ |
| for (iter = 0; iter < maxiter; iter++) { |
| buf = kmem_cache_alloc(c, GFP_KERNEL); |
| used_objects[iter] = buf; |
| if (buf == saved_ptr) { |
| fail = memcmp(buf_contents, buf, size); |
| for (i = 0; i <= iter; i++) |
| kmem_cache_free(c, used_objects[i]); |
| goto free_out; |
| } |
| } |
| |
| for (iter = 0; iter < maxiter; iter++) |
| kmem_cache_free(c, used_objects[iter]); |
| |
| free_out: |
| kfree(buf_contents); |
| kfree(used_objects); |
| out: |
| kmem_cache_destroy(c); |
| *total_failures += fail; |
| return 1; |
| } |
| |
| static int __init do_kmem_cache_size_bulk(int size, int *total_failures) |
| { |
| struct kmem_cache *c; |
| int i, iter, maxiter = 1024; |
| int num, bytes; |
| bool fail = false; |
| void *objects[10]; |
| |
| c = kmem_cache_create("test_cache", size, size, 0, NULL); |
| for (iter = 0; (iter < maxiter) && !fail; iter++) { |
| num = kmem_cache_alloc_bulk(c, GFP_KERNEL, ARRAY_SIZE(objects), |
| objects); |
| for (i = 0; i < num; i++) { |
| bytes = count_nonzero_bytes(objects[i], size); |
| if (bytes) |
| fail = true; |
| fill_with_garbage(objects[i], size); |
| } |
| |
| if (num) |
| kmem_cache_free_bulk(c, num, objects); |
| } |
| kmem_cache_destroy(c); |
| *total_failures += fail; |
| return 1; |
| } |
| |
| /* |
| * Test kmem_cache allocation by creating caches of different sizes, with and |
| * without constructors, with and without SLAB_TYPESAFE_BY_RCU. |
| */ |
| static int __init test_kmemcache(int *total_failures) |
| { |
| int failures = 0, num_tests = 0; |
| int i, flags, size; |
| bool ctor, rcu, zero; |
| |
| for (i = 0; i < 10; i++) { |
| size = 8 << i; |
| for (flags = 0; flags < 8; flags++) { |
| ctor = flags & 1; |
| rcu = flags & 2; |
| zero = flags & 4; |
| if (ctor & zero) |
| continue; |
| num_tests += do_kmem_cache_size(size, ctor, rcu, zero, |
| &failures); |
| } |
| num_tests += do_kmem_cache_size_bulk(size, &failures); |
| } |
| REPORT_FAILURES_IN_FN(); |
| *total_failures += failures; |
| return num_tests; |
| } |
| |
| /* Test the behavior of SLAB_TYPESAFE_BY_RCU caches of different sizes. */ |
| static int __init test_rcu_persistent(int *total_failures) |
| { |
| int failures = 0, num_tests = 0; |
| int i, size; |
| |
| for (i = 0; i < 10; i++) { |
| size = 8 << i; |
| num_tests += do_kmem_cache_rcu_persistent(size, &failures); |
| } |
| REPORT_FAILURES_IN_FN(); |
| *total_failures += failures; |
| return num_tests; |
| } |
| |
| /* |
| * Run the tests. Each test function returns the number of executed tests and |
| * updates |failures| with the number of failed tests. |
| */ |
| static int __init test_meminit_init(void) |
| { |
| int failures = 0, num_tests = 0; |
| |
| num_tests += test_pages(&failures); |
| num_tests += test_kvmalloc(&failures); |
| num_tests += test_kmemcache(&failures); |
| num_tests += test_rcu_persistent(&failures); |
| |
| if (failures == 0) |
| pr_info("all %d tests passed!\n", num_tests); |
| else |
| pr_info("failures: %d out of %d\n", failures, num_tests); |
| |
| return failures ? -EINVAL : 0; |
| } |
| module_init(test_meminit_init); |
| |
| MODULE_DESCRIPTION("Test cases for SL[AOU]B/page initialization at alloc/free time"); |
| MODULE_LICENSE("GPL"); |