diff options
| -rw-r--r-- | mm/kfence/core.c | 38 |
1 files changed, 21 insertions, 17 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index b61ef93d9f98..802905b1c89b 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -309,12 +309,19 @@ static inline bool set_canary_byte(u8 *addr) /* Check canary byte at @addr. */ static inline bool check_canary_byte(u8 *addr) { + struct kfence_metadata *meta; + unsigned long flags; + if (likely(*addr == KFENCE_CANARY_PATTERN(addr))) return true; atomic_long_inc(&counters[KFENCE_COUNTER_BUGS]); - kfence_report_error((unsigned long)addr, false, NULL, addr_to_metadata((unsigned long)addr), - KFENCE_ERROR_CORRUPTION); + + meta = addr_to_metadata((unsigned long)addr); + raw_spin_lock_irqsave(&meta->lock, flags); + kfence_report_error((unsigned long)addr, false, NULL, meta, KFENCE_ERROR_CORRUPTION); + raw_spin_unlock_irqrestore(&meta->lock, flags); + return false; } @@ -324,8 +331,6 @@ static __always_inline void for_each_canary(const struct kfence_metadata *meta, const unsigned long pageaddr = ALIGN_DOWN(meta->addr, PAGE_SIZE); unsigned long addr; - lockdep_assert_held(&meta->lock); - /* * We'll iterate over each canary byte per-side until fn() returns * false. However, we'll still iterate over the canary bytes to the @@ -414,8 +419,9 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g WRITE_ONCE(meta->cache, cache); meta->size = size; meta->alloc_stack_hash = alloc_stack_hash; + raw_spin_unlock_irqrestore(&meta->lock, flags); - for_each_canary(meta, set_canary_byte); + alloc_covered_add(alloc_stack_hash, 1); /* Set required struct page fields. */ page = virt_to_page(meta->addr); @@ -425,11 +431,8 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g if (IS_ENABLED(CONFIG_SLAB)) page->s_mem = addr; - raw_spin_unlock_irqrestore(&meta->lock, flags); - - alloc_covered_add(alloc_stack_hash, 1); - /* Memory initialization. */ + for_each_canary(meta, set_canary_byte); /* * We check slab_want_init_on_alloc() ourselves, rather than letting @@ -454,6 +457,7 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z { struct kcsan_scoped_access assert_page_exclusive; unsigned long flags; + bool init; raw_spin_lock_irqsave(&meta->lock, flags); @@ -481,6 +485,13 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z meta->unprotected_page = 0; } + /* Mark the object as freed. */ + metadata_update_state(meta, KFENCE_OBJECT_FREED, NULL, 0); + init = slab_want_init_on_free(meta->cache); + raw_spin_unlock_irqrestore(&meta->lock, flags); + + alloc_covered_add(meta->alloc_stack_hash, -1); + /* Check canary bytes for memory corruption. */ for_each_canary(meta, check_canary_byte); @@ -489,16 +500,9 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z * data is still there, and after a use-after-free is detected, we * unprotect the page, so the data is still accessible. */ - if (!zombie && unlikely(slab_want_init_on_free(meta->cache))) + if (!zombie && unlikely(init)) memzero_explicit(addr, meta->size); - /* Mark the object as freed. */ - metadata_update_state(meta, KFENCE_OBJECT_FREED, NULL, 0); - - raw_spin_unlock_irqrestore(&meta->lock, flags); - - alloc_covered_add(meta->alloc_stack_hash, -1); - /* Protect to detect use-after-frees. */ kfence_protect((unsigned long)addr); |