1 files changed, 31 insertions, 2 deletions

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 71c15438afcf..9377b0789edc 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -42,6 +42,10 @@ enum kasan_mode {
 
 extern enum kasan_mode kasan_mode __ro_after_init;
 
+extern unsigned long kasan_page_alloc_sample;
+extern unsigned int kasan_page_alloc_sample_order;
+DECLARE_PER_CPU(long, kasan_page_alloc_skip);
+
 static inline bool kasan_vmalloc_enabled(void)
 {
 	return static_branch_likely(&kasan_flag_vmalloc);
@@ -57,6 +61,24 @@ static inline bool kasan_sync_fault_possible(void)
 	return kasan_mode == KASAN_MODE_SYNC || kasan_mode == KASAN_MODE_ASYMM;
 }
 
+static inline bool kasan_sample_page_alloc(unsigned int order)
+{
+	/* Fast-path for when sampling is disabled. */
+	if (kasan_page_alloc_sample == 1)
+		return true;
+
+	if (order < kasan_page_alloc_sample_order)
+		return true;
+
+	if (this_cpu_dec_return(kasan_page_alloc_skip) < 0) {
+		this_cpu_write(kasan_page_alloc_skip,
+			       kasan_page_alloc_sample - 1);
+		return true;
+	}
+
+	return false;
+}
+
 #else /* CONFIG_KASAN_HW_TAGS */
 
 static inline bool kasan_async_fault_possible(void)
@@ -69,6 +91,11 @@ static inline bool kasan_sync_fault_possible(void)
 	return true;
 }
 
+static inline bool kasan_sample_page_alloc(unsigned int order)
+{
+	return true;
+}
+
 #endif /* CONFIG_KASAN_HW_TAGS */
 
 #ifdef CONFIG_KASAN_GENERIC
@@ -180,6 +207,7 @@ struct kasan_report_info {
 	void *first_bad_addr;
 	struct kmem_cache *cache;
 	void *object;
+	size_t alloc_size;
 
 	/* Filled in by the mode-specific reporting code. */
 	const char *bug_type;
@@ -269,7 +297,7 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
 		<< KASAN_SHADOW_SCALE_SHIFT);
 }
 
-static inline bool addr_has_metadata(const void *addr)
+static __always_inline bool addr_has_metadata(const void *addr)
 {
 	return (kasan_reset_tag(addr) >=
 		kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
@@ -288,7 +316,7 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write,
 
 #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
-static inline bool addr_has_metadata(const void *addr)
+static __always_inline bool addr_has_metadata(const void *addr)
 {
 	return (is_vmalloc_addr(addr) || virt_addr_valid(addr));
 }
@@ -296,6 +324,7 @@ static inline bool addr_has_metadata(const void *addr)
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
 
 void *kasan_find_first_bad_addr(void *addr, size_t size);
+size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache);
 void kasan_complete_mode_report_info(struct kasan_report_info *info);
 void kasan_metadata_fetch_row(char *buffer, void *row);