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authorFeng Tang <feng.tang@intel.com>2022-11-30 16:54:50 +0800
committerVlastimil Babka <vbabka@suse.cz>2022-11-30 23:15:23 +0100
commit4d9dd4b0ce88072ca2368dfdd5c92bc078366e1e (patch)
tree25f4f4c3c17903f781f541e73fc3bb9e09921312 /lib
parent946fa0dbf2d8923a587f7348adf16563d59f1b3d (diff)
mm/slub, kunit: add SLAB_SKIP_KFENCE flag for cache creation
When kfence is enabled, the buffer allocated from the test case could be from a kfence pool, and the operation could be also caught and reported by kfence first, causing the case to fail. With default kfence setting, this is very difficult to be triggered. By changing CONFIG_KFENCE_NUM_OBJECTS from 255 to 16383, and CONFIG_KFENCE_SAMPLE_INTERVAL from 100 to 5, the allocation from kfence did hit 7 times in different slub_kunit cases out of 900 times of boot test. To avoid this, initially we tried is_kfence_address() to check this and repeated allocation till finding a non-kfence address. Vlastimil Babka suggested SLAB_SKIP_KFENCE flag could be used to achieve this, and better add a wrapper function for simplifying cache creation. Signed-off-by: Feng Tang <feng.tang@intel.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Diffstat (limited to 'lib')
-rw-r--r--lib/slub_kunit.c35
1 files changed, 25 insertions, 10 deletions
diff --git a/lib/slub_kunit.c b/lib/slub_kunit.c
index 7a0564d7cb7a..5b0c8e7eb6dc 100644
--- a/lib/slub_kunit.c
+++ b/lib/slub_kunit.c
@@ -9,10 +9,25 @@
static struct kunit_resource resource;
static int slab_errors;
+/*
+ * Wrapper function for kmem_cache_create(), which reduces 2 parameters:
+ * 'align' and 'ctor', and sets SLAB_SKIP_KFENCE flag to avoid getting an
+ * object from kfence pool, where the operation could be caught by both
+ * our test and kfence sanity check.
+ */
+static struct kmem_cache *test_kmem_cache_create(const char *name,
+ unsigned int size, slab_flags_t flags)
+{
+ struct kmem_cache *s = kmem_cache_create(name, size, 0,
+ (flags | SLAB_NO_USER_FLAGS), NULL);
+ s->flags |= SLAB_SKIP_KFENCE;
+ return s;
+}
+
static void test_clobber_zone(struct kunit *test)
{
- struct kmem_cache *s = kmem_cache_create("TestSlub_RZ_alloc", 64, 0,
- SLAB_RED_ZONE|SLAB_NO_USER_FLAGS, NULL);
+ struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_alloc", 64,
+ SLAB_RED_ZONE);
u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
kasan_disable_current();
@@ -29,8 +44,8 @@ static void test_clobber_zone(struct kunit *test)
#ifndef CONFIG_KASAN
static void test_next_pointer(struct kunit *test)
{
- struct kmem_cache *s = kmem_cache_create("TestSlub_next_ptr_free", 64, 0,
- SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
+ struct kmem_cache *s = test_kmem_cache_create("TestSlub_next_ptr_free",
+ 64, SLAB_POISON);
u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
unsigned long tmp;
unsigned long *ptr_addr;
@@ -74,8 +89,8 @@ static void test_next_pointer(struct kunit *test)
static void test_first_word(struct kunit *test)
{
- struct kmem_cache *s = kmem_cache_create("TestSlub_1th_word_free", 64, 0,
- SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
+ struct kmem_cache *s = test_kmem_cache_create("TestSlub_1th_word_free",
+ 64, SLAB_POISON);
u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
kmem_cache_free(s, p);
@@ -89,8 +104,8 @@ static void test_first_word(struct kunit *test)
static void test_clobber_50th_byte(struct kunit *test)
{
- struct kmem_cache *s = kmem_cache_create("TestSlub_50th_word_free", 64, 0,
- SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
+ struct kmem_cache *s = test_kmem_cache_create("TestSlub_50th_word_free",
+ 64, SLAB_POISON);
u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
kmem_cache_free(s, p);
@@ -105,8 +120,8 @@ static void test_clobber_50th_byte(struct kunit *test)
static void test_clobber_redzone_free(struct kunit *test)
{
- struct kmem_cache *s = kmem_cache_create("TestSlub_RZ_free", 64, 0,
- SLAB_RED_ZONE|SLAB_NO_USER_FLAGS, NULL);
+ struct kmem_cache *s = test_kmem_cache_create("TestSlub_RZ_free", 64,
+ SLAB_RED_ZONE);
u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
kasan_disable_current();