[PATCH RFC 3/3] kfence: Make test case compatible with run time set sample interval

From: Peng Liu
Date: Sun Jan 23 2022 - 21:38:16 EST


The parameter kfence_sample_interval can be set via boot parameter
and late shell command. However, KFENCE test case just use compile
time CONFIG_KFENCE_SAMPLE_INTERVAL, this will make KFENCE test case
not run as user desired. This patch will make KFENCE test case
compatible with run-time-set sample interval.

Signed-off-by: Peng Liu <liupeng256@xxxxxxxxxx>
---
include/linux/kfence.h | 2 ++
mm/kfence/core.c | 3 ++-
mm/kfence/kfence_test.c | 8 ++++----
3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/kfence.h b/include/linux/kfence.h
index bf91b76b87ee..0fc913a7f017 100644
--- a/include/linux/kfence.h
+++ b/include/linux/kfence.h
@@ -19,6 +19,8 @@

extern bool kfence_enabled;
extern unsigned long kfence_num_objects;
+extern unsigned long kfence_sample_interval;
+
/*
* We allocate an even number of pages, as it simplifies calculations to map
* address to metadata indices; effectively, the very first page serves as an
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 2301923182b8..e2fcae34cc84 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -50,7 +50,8 @@

bool kfence_enabled __read_mostly;

-static unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL;
+unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL;
+EXPORT_SYMBOL(kfence_sample_interval); /* Export for test modules. */

#ifdef MODULE_PARAM_PREFIX
#undef MODULE_PARAM_PREFIX
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index 084e3a55aebb..97ff3a133f11 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -268,13 +268,13 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
* 100x the sample interval should be more than enough to ensure we get
* a KFENCE allocation eventually.
*/
- timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL);
+ timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
/*
* Especially for non-preemption kernels, ensure the allocation-gate
* timer can catch up: after @resched_after, every failed allocation
* attempt yields, to ensure the allocation-gate timer is scheduled.
*/
- resched_after = jiffies + msecs_to_jiffies(CONFIG_KFENCE_SAMPLE_INTERVAL);
+ resched_after = jiffies + msecs_to_jiffies(kfence_sample_interval);
do {
if (test_cache)
alloc = kmem_cache_alloc(test_cache, gfp);
@@ -608,7 +608,7 @@ static void test_gfpzero(struct kunit *test)
int i;

/* Skip if we think it'd take too long. */
- KFENCE_TEST_REQUIRES(test, CONFIG_KFENCE_SAMPLE_INTERVAL <= 100);
+ KFENCE_TEST_REQUIRES(test, kfence_sample_interval <= 100);

setup_test_cache(test, size, 0, NULL);
buf1 = test_alloc(test, size, GFP_KERNEL, ALLOCATE_ANY);
@@ -739,7 +739,7 @@ static void test_memcache_alloc_bulk(struct kunit *test)
* 100x the sample interval should be more than enough to ensure we get
* a KFENCE allocation eventually.
*/
- timeout = jiffies + msecs_to_jiffies(100 * CONFIG_KFENCE_SAMPLE_INTERVAL);
+ timeout = jiffies + msecs_to_jiffies(100 * kfence_sample_interval);
do {
void *objects[100];
int i, num = kmem_cache_alloc_bulk(test_cache, GFP_ATOMIC, ARRAY_SIZE(objects),
--
2.18.0.huawei.25