summary refs log tree commit diff
path: root/mm
diff options
context:
space:
mode:
Diffstat (limited to 'mm')
-rw-r--r--mm/slub.c25
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)