kfence: make test case compatible with run time set sample interval

The parameter kfence_sample_interval can be set via boot parameter and
late shell command, which is convenient for automated tests and KFENCE
parameter optimization.  However, KFENCE test case just uses
compile-time CONFIG_KFENCE_SAMPLE_INTERVAL, which will make KFENCE test
case not run as users desired.  Export kfence_sample_interval, so that
KFENCE test case can use run-time-set sample interval.

Link: https://lkml.kernel.org/r/20220207034432.185532-1-liupeng256@huawei.com
Signed-off-by: Peng Liu <liupeng256@huawei.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Christian Knig <christian.koenig@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/kfence.h b/include/linux/kfence.h
index 4b5e3679a72c78caf5a6aa2c185658328403fa2f..f49e64222628ae3a1a15df5c3a111c9f434b135c 100644 (file)
--- a/include/linux/kfence.h
+++ b/include/linux/kfence.h
@@ -17,6 +17,8 @@
 #include <linux/atomic.h>
 #include <linux/static_key.h>
 
+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 5ad40e3add457db1e788314e8e46eb0b2dfb4e61..13128fa1306256e617a7641fcc78fcafa40fdc5d 100644 (file)
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -47,7 +47,8 @@
 
 static 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_GPL(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 a22b1af85577d69b9df1f404a010eec6df4d000a..50dbb815a2a8308920e7e69a2829d70240f2e520 100644 (file)
--- 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),