diff options
authorAlexander Potapenko <glider@google.com>2016-03-25 14:21:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-25 16:37:42 -0700
commite6e8379c876de16c6b78f83b15d5ac32c79cb440 (patch)
parentaaf4fb712b8311d8b950e89937479d61e9c25ba8 (diff)
kasan: modify kmalloc_large_oob_right(), add kmalloc_pagealloc_oob_right()
This patchset implements SLAB support for KASAN Unlike SLUB, SLAB doesn't store allocation/deallocation stacks for heap objects, therefore we reimplement this feature in mm/kasan/stackdepot.c. The intention is to ultimately switch SLUB to use this implementation as well, which will save a lot of memory (right now SLUB bloats each object by 256 bytes to store the allocation/deallocation stacks). Also neither SLUB nor SLAB delay the reuse of freed memory chunks, which is necessary for better detection of use-after-free errors. We introduce memory quarantine (mm/kasan/quarantine.c), which allows delayed reuse of deallocated memory. This patch (of 7): Rename kmalloc_large_oob_right() to kmalloc_pagealloc_oob_right(), as the test only checks the page allocator functionality. Also reimplement kmalloc_large_oob_right() so that the test allocates a large enough chunk of memory that still does not trigger the page allocator fallback. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 27 insertions, 1 deletions
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index c32f3b0048dc..90ad74f71535 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -65,11 +65,34 @@ static noinline void __init kmalloc_node_oob_right(void)
-static noinline void __init kmalloc_large_oob_right(void)
+static noinline void __init kmalloc_pagealloc_oob_right(void)
char *ptr;
size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
+ /* Allocate a chunk that does not fit into a SLUB cache to trigger
+ * the page allocator fallback.
+ */
+ pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
+ ptr = kmalloc(size, GFP_KERNEL);
+ if (!ptr) {
+ pr_err("Allocation failed\n");
+ return;
+ }
+ ptr[size] = 0;
+ kfree(ptr);
+static noinline void __init kmalloc_large_oob_right(void)
+ char *ptr;
+ size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
+ /* Allocate a chunk that is large enough, but still fits into a slab
+ * and does not trigger the page allocator fallback in SLUB.
+ */
pr_info("kmalloc large allocation: out-of-bounds to right\n");
ptr = kmalloc(size, GFP_KERNEL);
if (!ptr) {
@@ -324,6 +347,9 @@ static int __init kmalloc_tests_init(void)
+ kmalloc_pagealloc_oob_right();

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