1 files changed, 25 insertions, 0 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 6833b73ef6b3..37555ad8894d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -20,6 +20,7 @@
 #include <linux/proc_fs.h>
 #include <linux/notifier.h>
 #include <linux/seq_file.h>
+#include <linux/kasan.h>
 #include <linux/kmemcheck.h>
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
@@ -468,12 +469,30 @@ static char *slub_debug_slabs;
 static int disable_higher_order_debug;
 
 /*
+ * slub is about to manipulate internal object metadata.  This memory lies
+ * outside the range of the allocated object, so accessing it would normally
+ * be reported by kasan as a bounds error.  metadata_access_enable() is used
+ * to tell kasan that these accesses are OK.
+ */
+static inline void metadata_access_enable(void)
+{
+        kasan_disable_current();
+}
+
+static inline void metadata_access_disable(void)
+{
+        kasan_enable_current();
+}
+
+/*
  * Object debugging
  */
 static void print_section(char *text, u8 *addr, unsigned int length)
 {
+        metadata_access_enable();
         print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
                         length, 1);
+        metadata_access_disable();
 }
 
 static struct track *get_track(struct kmem_cache *s, void *object,
@@ -503,7 +522,9 @@ static void set_track(struct kmem_cache *s, void *object,
                 trace.max_entries = TRACK_ADDRS_COUNT;
                 trace.entries = p->addrs;
                 trace.skip = 3;
+                metadata_access_enable();
                 save_stack_trace(&trace);
+                metadata_access_disable();
 
                 /* See rant in lockdep.c */
                 if (trace.nr_entries != 0 &&
@@ -677,7 +698,9 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
         u8 *fault;
         u8 *end;
 
+        metadata_access_enable();
         fault = memchr_inv(start, value, bytes);
+        metadata_access_disable();
         if (!fault)
                 return 1;
 
@@ -770,7 +793,9 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
         if (!remainder)
                 return 1;
 
+        metadata_access_enable();
         fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
+        metadata_access_disable();
         if (!fault)
                 return 1;
         while (end > fault && end[-1] == POISON_INUSE)