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-rw-r--r--mm/kfence/core.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 4e7cd4c8e687..4b5e5a3d3a63 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -360,6 +360,9 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
unsigned long flags;
struct slab *slab;
void *addr;
+ const bool random_right_allocate = prandom_u32_max(2);
+ const bool random_fault = CONFIG_KFENCE_STRESS_TEST_FAULTS &&
+ !prandom_u32_max(CONFIG_KFENCE_STRESS_TEST_FAULTS);
/* Try to obtain a free object. */
raw_spin_lock_irqsave(&kfence_freelist_lock, flags);
@@ -404,7 +407,7 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
* is that the out-of-bounds accesses detected are deterministic for
* such allocations.
*/
- if (prandom_u32_max(2)) {
+ if (random_right_allocate) {
/* Allocate on the "right" side, re-calculate address. */
meta->addr += PAGE_SIZE - size;
meta->addr = ALIGN_DOWN(meta->addr, cache->align);
@@ -444,7 +447,7 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
if (cache->ctor)
cache->ctor(addr);
- if (CONFIG_KFENCE_STRESS_TEST_FAULTS && !prandom_u32_max(CONFIG_KFENCE_STRESS_TEST_FAULTS))
+ if (random_fault)
kfence_protect(meta->addr); /* Random "faults" by protecting the object. */
atomic_long_inc(&counters[KFENCE_COUNTER_ALLOCATED]);