2 files changed, 25 insertions, 1 deletions

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 4b9f85c963d0..0fdc798e3ff7 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -1,6 +1,7 @@
 #ifndef _LINUX_KASAN_H
 #define _LINUX_KASAN_H
 
+#include <linux/sched.h>
 #include <linux/types.h>
 
 struct kmem_cache;
@@ -13,7 +14,6 @@ struct vm_struct;
 
 #include <asm/kasan.h>
 #include <asm/pgtable.h>
-#include <linux/sched.h>
 
 extern unsigned char kasan_zero_page[PAGE_SIZE];
 extern pte_t kasan_zero_pte[PTRS_PER_PTE];
@@ -43,6 +43,8 @@ static inline void kasan_disable_current(void)
 
 void kasan_unpoison_shadow(const void *address, size_t size);
 
+void kasan_unpoison_task_stack(struct task_struct *task);
+
 void kasan_alloc_pages(struct page *page, unsigned int order);
 void kasan_free_pages(struct page *page, unsigned int order);
 
@@ -66,6 +68,8 @@ void kasan_free_shadow(const struct vm_struct *vm);
 
 static inline void kasan_unpoison_shadow(const void *address, size_t size) {}
 
+static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
+
 static inline void kasan_enable_current(void) {}
 static inline void kasan_disable_current(void) {}
 
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index bc0a8d8b8f42..1ad20ade8c91 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -20,6 +20,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/kmemleak.h>
+#include <linux/linkage.h>
 #include <linux/memblock.h>
 #include <linux/memory.h>
 #include <linux/mm.h>
@@ -60,6 +61,25 @@ void kasan_unpoison_shadow(const void *address, size_t size)
         }
 }
 
+static void __kasan_unpoison_stack(struct task_struct *task, void *sp)
+{
+        void *base = task_stack_page(task);
+        size_t size = sp - base;
+
+        kasan_unpoison_shadow(base, size);
+}
+
+/* Unpoison the entire stack for a task. */
+void kasan_unpoison_task_stack(struct task_struct *task)
+{
+        __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
+}
+
+/* Unpoison the stack for the current task beyond a watermark sp value. */
+asmlinkage void kasan_unpoison_remaining_stack(void *sp)
+{
+        __kasan_unpoison_stack(current, sp);
+}
 
 /*
  * All functions below always inlined so compiler could