lib/slub_kunit.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <kunit/test.h>
   3 #include <linux/mm.h>
   4 #include <linux/slab.h>
   5 #include <linux/module.h>
   6 #include <linux/kernel.h>
   7 #include "../mm/slab.h"
   8
   9 static struct kunit_resource resource;
  10 static int slab_errors;
  11
  12 static void test_clobber_zone(struct kunit *test)
  13 {
  14         struct kmem_cache *s = kmem_cache_create("TestSlub_RZ_alloc", 64, 0,
  15                                 SLAB_RED_ZONE|SLAB_NO_USER_FLAGS, NULL);
  16         u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
  17
  18         kasan_disable_current();
  19         p[64] = 0x12;
  20
  21         validate_slab_cache(s);
  22         KUNIT_EXPECT_EQ(test, 2, slab_errors);
  23
  24         kasan_enable_current();
  25         kmem_cache_free(s, p);
  26         kmem_cache_destroy(s);
  27 }
  28
  29 #ifndef CONFIG_KASAN
  30 static void test_next_pointer(struct kunit *test)
  31 {
  32         struct kmem_cache *s = kmem_cache_create("TestSlub_next_ptr_free", 64, 0,
  33                                 SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
  34         u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
  35         unsigned long tmp;
  36         unsigned long *ptr_addr;
  37
  38         kmem_cache_free(s, p);
  39
  40         ptr_addr = (unsigned long *)(p + s->offset);
  41         tmp = *ptr_addr;
  42         p[s->offset] = 0x12;
  43
  44         /*
  45          * Expecting three errors.
  46          * One for the corrupted freechain and the other one for the wrong
  47          * count of objects in use. The third error is fixing broken cache.
  48          */
  49         validate_slab_cache(s);
  50         KUNIT_EXPECT_EQ(test, 3, slab_errors);
  51
  52         /*
  53          * Try to repair corrupted freepointer.
  54          * Still expecting two errors. The first for the wrong count
  55          * of objects in use.
  56          * The second error is for fixing broken cache.
  57          */
  58         *ptr_addr = tmp;
  59         slab_errors = 0;
  60
  61         validate_slab_cache(s);
  62         KUNIT_EXPECT_EQ(test, 2, slab_errors);
  63
  64         /*
  65          * Previous validation repaired the count of objects in use.
  66          * Now expecting no error.
  67          */
  68         slab_errors = 0;
  69         validate_slab_cache(s);
  70         KUNIT_EXPECT_EQ(test, 0, slab_errors);
  71
  72         kmem_cache_destroy(s);
  73 }
  74
  75 static void test_first_word(struct kunit *test)
  76 {
  77         struct kmem_cache *s = kmem_cache_create("TestSlub_1th_word_free", 64, 0,
  78                                 SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
  79         u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
  80
  81         kmem_cache_free(s, p);
  82         *p = 0x78;
  83
  84         validate_slab_cache(s);
  85         KUNIT_EXPECT_EQ(test, 2, slab_errors);
  86
  87         kmem_cache_destroy(s);
  88 }
  89
  90 static void test_clobber_50th_byte(struct kunit *test)
  91 {
  92         struct kmem_cache *s = kmem_cache_create("TestSlub_50th_word_free", 64, 0,
  93                                 SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
  94         u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
  95
  96         kmem_cache_free(s, p);
  97         p[50] = 0x9a;
  98
  99         validate_slab_cache(s);
 100         KUNIT_EXPECT_EQ(test, 2, slab_errors);
 101
 102         kmem_cache_destroy(s);
 103 }
 104 #endif
 105
 106 static void test_clobber_redzone_free(struct kunit *test)
 107 {
 108         struct kmem_cache *s = kmem_cache_create("TestSlub_RZ_free", 64, 0,
 109                                 SLAB_RED_ZONE|SLAB_NO_USER_FLAGS, NULL);
 110         u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
 111
 112         kasan_disable_current();
 113         kmem_cache_free(s, p);
 114         p[64] = 0xab;
 115
 116         validate_slab_cache(s);
 117         KUNIT_EXPECT_EQ(test, 2, slab_errors);
 118
 119         kasan_enable_current();
 120         kmem_cache_destroy(s);
 121 }
 122
 123 static int test_init(struct kunit *test)
 124 {
 125         slab_errors = 0;
 126
 127         kunit_add_named_resource(test, NULL, NULL, &resource,
 128                                         "slab_errors", &slab_errors);
 129         return 0;
 130 }
 131
 132 static struct kunit_case test_cases[] = {
 133         KUNIT_CASE(test_clobber_zone),
 134
 135 #ifndef CONFIG_KASAN
 136         KUNIT_CASE(test_next_pointer),
 137         KUNIT_CASE(test_first_word),
 138         KUNIT_CASE(test_clobber_50th_byte),
 139 #endif
 140
 141         KUNIT_CASE(test_clobber_redzone_free),
 142         {}
 143 };
 144
 145 static struct kunit_suite test_suite = {
 146         .name = "slub_test",
 147         .init = test_init,
 148         .test_cases = test_cases,
 149 };
 150 kunit_test_suite(test_suite);
 151
 152 MODULE_LICENSE("GPL");