lib: introduce test_meminit module (5015a300) · Commits · 戴 / test

lib/Kconfig.debug

+8 −0

Original line number	Diff line number	Diff line
		@@ -2076,6 +2076,14 @@ config TEST_STACKINIT

		If unsure, say N.

		config TEST_MEMINIT
		tristate "Test heap/page initialization"
		help
		Test if the kernel is zero-initializing heap and page allocations.
		This can be useful to test init_on_alloc and init_on_free features.

		If unsure, say N.

		endif # RUNTIME_TESTING_MENU

		config MEMTEST

lib/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -92,6 +92,7 @@ obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o
		obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o
		obj-$(CONFIG_TEST_STACKINIT) += test_stackinit.o
		obj-$(CONFIG_TEST_BLACKHOLE_DEV) += test_blackhole_dev.o
		obj-$(CONFIG_TEST_MEMINIT) += test_meminit.o

		obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/

lib/test_meminit.c

0 → 100644

+362 −0

Original line number	Diff line number	Diff line
		// 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, size_t size, size_t skip)
		{
		unsigned int p = (unsigned int )ptr;
		int i = 0;

		if (skip) {
		WARN_ON(skip > size);
		p += 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);
		buf = page_address(page);
		fill_with_garbage(buf, size);
		__free_pages(page, order);

		page = alloc_pages(GFP_KERNEL, order);
		buf = page_address(page);
		if (count_nonzero_bytes(buf, size))
		(*total_failures)++;
		fill_with_garbage(buf, size);
		__free_pages(page, order);
		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 < 10; 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);
		fill_with_garbage(buf, size);
		kfree(buf);

		buf = kmalloc(size, GFP_KERNEL);
		if (count_nonzero_bytes(buf, size))
		(*total_failures)++;
		fill_with_garbage(buf, size);
		kfree(buf);
		return 1;
		}

		/* Test vmalloc() with given parameters. */
		static int __init do_vmalloc_size(size_t size, int *total_failures)
		{
		void *buf;

		buf = vmalloc(size);
		fill_with_garbage(buf, size);
		vfree(buf);

		buf = vmalloc(size);
		if (count_nonzero_bytes(buf, size))
		(*total_failures)++;
		fill_with_garbage(buf, size);
		vfree(buf);
		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;
		}

		/*
		* 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++) {
		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 this is an RCU cache, use a critical section to ensure we
		* can touch objects after they're freed.
		*/
		if (want_rcu) {
		rcu_read_lock();
		/*
		* Copy the buffer to check that it's not wiped on
		* free().
		*/
		buf_copy = kmalloc(size, GFP_KERNEL);
		if (buf_copy)
		memcpy(buf_copy, buf, size);
		}
		kmem_cache_free(c, buf);
		if (want_rcu) {
		/*
		* 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);
		saved_ptr = buf;
		fill_with_garbage(buf, size);
		buf_contents = kmalloc(size, GFP_KERNEL);
		if (!buf_contents)
		goto out;
		used_objects = kmalloc_array(maxiter, sizeof(void *), GFP_KERNEL);
		if (!used_objects) {
		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;
		}
		}

		free_out:
		kmem_cache_destroy(c);
		kfree(buf_contents);
		kfree(used_objects);
		out:
		*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);
		}
		}
		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_LICENSE("GPL");

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