5 files changed, 16 insertions, 7 deletions

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 72ba725ddf9c..5fa48a21d73e 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -5,6 +5,7 @@
 
 struct kmem_cache;
 struct page;
+struct vm_struct;
 
 #ifdef CONFIG_KASAN
 
@@ -52,7 +53,7 @@ void kasan_slab_free(struct kmem_cache *s, void *object);
 #define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
 
 int kasan_module_alloc(void *addr, size_t size);
-void kasan_module_free(void *addr);
+void kasan_free_shadow(const struct vm_struct *vm);
 
 #else /* CONFIG_KASAN */
 
@@ -82,7 +83,7 @@ static inline void kasan_slab_alloc(struct kmem_cache *s, void *object) {}
 static inline void kasan_slab_free(struct kmem_cache *s, void *object) {}
 
 static inline int kasan_module_alloc(void *addr, size_t size) { return 0; }
-static inline void kasan_module_free(void *addr) {}
+static inline void kasan_free_shadow(const struct vm_struct *vm) {}
 
 #endif /* CONFIG_KASAN */
 
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 7d7acb35603d..0ec598381f97 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -17,6 +17,7 @@ struct vm_area_struct;		/* vma defining user mapping in mm_types.h */
 #define VM_VPAGES               0x00000010      /* buffer for pages was vmalloc'ed */
 #define VM_UNINITIALIZED        0x00000020      /* vm_struct is not fully initialized */
 #define VM_NO_GUARD             0x00000040      /* don't add guard page */
+#define VM_KASAN                0x00000080      /* has allocated kasan shadow memory */
 /* bits [20..32] reserved for arch specific ioremap internals */
 
 /*
diff --git a/kernel/module.c b/kernel/module.c
index cc93cf68653c..b3d634ed06c9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -56,7 +56,6 @@
 #include <linux/async.h>
 #include <linux/percpu.h>
 #include <linux/kmemleak.h>
-#include <linux/kasan.h>
 #include <linux/jump_label.h>
 #include <linux/pfn.h>
 #include <linux/bsearch.h>
@@ -1814,7 +1813,6 @@ static void unset_module_init_ro_nx(struct module *mod) { }
 void __weak module_memfree(void *module_region)
 {
         vfree(module_region);
-        kasan_module_free(module_region);
 }
 
 void __weak module_arch_cleanup(struct module *mod)
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index 78fee632a7ee..936d81661c47 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -29,6 +29,7 @@
 #include <linux/stacktrace.h>
 #include <linux/string.h>
 #include <linux/types.h>
+#include <linux/vmalloc.h>
 #include <linux/kasan.h>
 
 #include "kasan.h"
@@ -414,12 +415,19 @@ int kasan_module_alloc(void *addr, size_t size)
                         GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
                         __builtin_return_address(0));
-        return ret ? 0 : -ENOMEM;
+
+        if (ret) {
+                find_vm_area(addr)->flags |= VM_KASAN;
+                return 0;
+        }
+
+        return -ENOMEM;
 }
 
-void kasan_module_free(void *addr)
+void kasan_free_shadow(const struct vm_struct *vm)
 {
-        vfree(kasan_mem_to_shadow(addr));
+        if (vm->flags & VM_KASAN)
+                vfree(kasan_mem_to_shadow(vm->addr));
 }
 
 static void register_global(struct kasan_global *global)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 35b25e1340ca..49abccf29a29 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1418,6 +1418,7 @@ struct vm_struct *remove_vm_area(const void *addr)
                 spin_unlock(&vmap_area_lock);
 
                 vmap_debug_free_range(va->va_start, va->va_end);
+                kasan_free_shadow(vm);
                 free_unmap_vmap_area(va);
                 vm->size -= PAGE_SIZE;