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080c8579c3
Danilo Krummrich raised issue about krealloc+GFP_ZERO [1], and Vlastimil suggested to add some test case which can sanity test the kmalloc-redzone and zeroing by utilizing the kmalloc's 'orig_size' debug feature. It covers the grow and shrink case of krealloc() re-using current kmalloc object, and the case of re-allocating a new bigger object. [1]. https://lore.kernel.org/lkml/20240812223707.32049-1-dakr@kernel.org/ Suggested-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
270 lines
6.3 KiB
C
270 lines
6.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <kunit/test.h>
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#include <kunit/test-bug.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/rcupdate.h>
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#include "../mm/slab.h"
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static struct kunit_resource resource;
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static int slab_errors;
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/*
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* Wrapper function for kmem_cache_create(), which reduces 2 parameters:
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* 'align' and 'ctor', and sets SLAB_SKIP_KFENCE flag to avoid getting an
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* object from kfence pool, where the operation could be caught by both
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* our test and kfence sanity check.
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*/
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static struct kmem_cache *test_kmem_cache_create(const char *name,
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unsigned int size, slab_flags_t flags)
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{
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struct kmem_cache *s = kmem_cache_create(name, size, 0,
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(flags | SLAB_NO_USER_FLAGS), NULL);
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s->flags |= SLAB_SKIP_KFENCE;
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return s;
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}
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static void test_clobber_zone(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_alloc", 64,
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SLAB_RED_ZONE);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kasan_disable_current();
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p[64] = 0x12;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kasan_enable_current();
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kmem_cache_free(s, p);
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kmem_cache_destroy(s);
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}
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#ifndef CONFIG_KASAN
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static void test_next_pointer(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_next_ptr_free",
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64, SLAB_POISON);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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unsigned long tmp;
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unsigned long *ptr_addr;
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kmem_cache_free(s, p);
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ptr_addr = (unsigned long *)(p + s->offset);
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tmp = *ptr_addr;
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p[s->offset] = ~p[s->offset];
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/*
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* Expecting three errors.
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* One for the corrupted freechain and the other one for the wrong
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* count of objects in use. The third error is fixing broken cache.
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*/
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 3, slab_errors);
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/*
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* Try to repair corrupted freepointer.
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* Still expecting two errors. The first for the wrong count
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* of objects in use.
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* The second error is for fixing broken cache.
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*/
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*ptr_addr = tmp;
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slab_errors = 0;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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/*
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* Previous validation repaired the count of objects in use.
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* Now expecting no error.
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*/
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slab_errors = 0;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 0, slab_errors);
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kmem_cache_destroy(s);
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}
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static void test_first_word(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_1th_word_free",
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64, SLAB_POISON);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kmem_cache_free(s, p);
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*p = 0x78;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kmem_cache_destroy(s);
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}
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static void test_clobber_50th_byte(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_50th_word_free",
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64, SLAB_POISON);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kmem_cache_free(s, p);
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p[50] = 0x9a;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kmem_cache_destroy(s);
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}
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#endif
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static void test_clobber_redzone_free(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_free", 64,
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SLAB_RED_ZONE);
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u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
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kasan_disable_current();
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kmem_cache_free(s, p);
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p[64] = 0xab;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kasan_enable_current();
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kmem_cache_destroy(s);
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}
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static void test_kmalloc_redzone_access(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_kmalloc", 32,
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SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE);
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u8 *p = alloc_hooks(__kmalloc_cache_noprof(s, GFP_KERNEL, 18));
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kasan_disable_current();
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/* Suppress the -Warray-bounds warning */
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OPTIMIZER_HIDE_VAR(p);
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p[18] = 0xab;
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p[19] = 0xab;
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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kasan_enable_current();
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kmem_cache_free(s, p);
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kmem_cache_destroy(s);
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}
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struct test_kfree_rcu_struct {
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struct rcu_head rcu;
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};
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static void test_kfree_rcu(struct kunit *test)
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{
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struct kmem_cache *s;
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struct test_kfree_rcu_struct *p;
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if (IS_BUILTIN(CONFIG_SLUB_KUNIT_TEST))
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kunit_skip(test, "can't do kfree_rcu() when test is built-in");
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s = test_kmem_cache_create("TestSlub_kfree_rcu",
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sizeof(struct test_kfree_rcu_struct),
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SLAB_NO_MERGE);
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p = kmem_cache_alloc(s, GFP_KERNEL);
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kfree_rcu(p, rcu);
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kmem_cache_destroy(s);
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KUNIT_EXPECT_EQ(test, 0, slab_errors);
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}
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static void test_leak_destroy(struct kunit *test)
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{
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_leak_destroy",
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64, SLAB_NO_MERGE);
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kmem_cache_alloc(s, GFP_KERNEL);
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kmem_cache_destroy(s);
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KUNIT_EXPECT_EQ(test, 2, slab_errors);
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}
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static void test_krealloc_redzone_zeroing(struct kunit *test)
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{
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u8 *p;
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int i;
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struct kmem_cache *s = test_kmem_cache_create("TestSlub_krealloc", 64,
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SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE);
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p = alloc_hooks(__kmalloc_cache_noprof(s, GFP_KERNEL, 48));
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memset(p, 0xff, 48);
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kasan_disable_current();
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OPTIMIZER_HIDE_VAR(p);
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/* Test shrink */
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p = krealloc(p, 40, GFP_KERNEL | __GFP_ZERO);
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for (i = 40; i < 64; i++)
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KUNIT_EXPECT_EQ(test, p[i], SLUB_RED_ACTIVE);
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/* Test grow within the same 64B kmalloc object */
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p = krealloc(p, 56, GFP_KERNEL | __GFP_ZERO);
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for (i = 40; i < 56; i++)
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KUNIT_EXPECT_EQ(test, p[i], 0);
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for (i = 56; i < 64; i++)
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KUNIT_EXPECT_EQ(test, p[i], SLUB_RED_ACTIVE);
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validate_slab_cache(s);
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KUNIT_EXPECT_EQ(test, 0, slab_errors);
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memset(p, 0xff, 56);
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/* Test grow with allocating a bigger 128B object */
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p = krealloc(p, 112, GFP_KERNEL | __GFP_ZERO);
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for (i = 0; i < 56; i++)
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KUNIT_EXPECT_EQ(test, p[i], 0xff);
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for (i = 56; i < 112; i++)
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KUNIT_EXPECT_EQ(test, p[i], 0);
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kfree(p);
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kasan_enable_current();
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kmem_cache_destroy(s);
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}
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static int test_init(struct kunit *test)
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{
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slab_errors = 0;
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kunit_add_named_resource(test, NULL, NULL, &resource,
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"slab_errors", &slab_errors);
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return 0;
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}
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static struct kunit_case test_cases[] = {
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KUNIT_CASE(test_clobber_zone),
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#ifndef CONFIG_KASAN
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KUNIT_CASE(test_next_pointer),
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KUNIT_CASE(test_first_word),
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KUNIT_CASE(test_clobber_50th_byte),
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#endif
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KUNIT_CASE(test_clobber_redzone_free),
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KUNIT_CASE(test_kmalloc_redzone_access),
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KUNIT_CASE(test_kfree_rcu),
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KUNIT_CASE(test_leak_destroy),
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KUNIT_CASE(test_krealloc_redzone_zeroing),
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{}
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};
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static struct kunit_suite test_suite = {
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.name = "slub_test",
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.init = test_init,
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.test_cases = test_cases,
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};
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kunit_test_suite(test_suite);
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MODULE_LICENSE("GPL");
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