kasan: fix invalid-free test crashing the kernel

When an invalid-free is triggered by one of the KASAN tests, the object
doesn't actually get freed.  This later leads to a BUG failure in
kmem_cache_destroy that checks that there are no allocated objects in
the cache that is being destroyed.

Fix this by calling kmem_cache_free with the proper object address after
the call that triggers invalid-free.

Link: http://lkml.kernel.org/r/286eaefc0a6c3fa9b83b87e7d6dc0fbb5b5c9926.1519924383.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <[email protected]>
Acked-by: Andrey Ryabinin <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Nick Terrell <[email protected]>
Cc: Chris Mason <[email protected]>
Cc: Yury Norov <[email protected]>
Cc: Al Viro <[email protected]>
Cc: "Luis R . Rodriguez" <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: "Paul E . McKenney" <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: "Jason A . Donenfeld" <[email protected]>
Cc: Kostya Serebryany <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 98854a64b014dbbf761deb2c4fcda1512a456b68..ec657105edbf08e2c87ea1acc8288e6e10bf6e6b 100644 (file)
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -567,7 +567,15 @@ static noinline void __init kmem_cache_invalid_free(void)
                return;
        }
 
+       /* Trigger invalid free, the object doesn't get freed */
        kmem_cache_free(cache, p + 1);
+
+       /*
+        * Properly free the object to prevent the "Objects remaining in
+        * test_cache on __kmem_cache_shutdown" BUG failure.
+        */
+       kmem_cache_free(cache, p);
+
        kmem_cache_destroy(cache);
 }