From: Greg Thelen <gthelen@xxxxxxxxxx> Subject: kasan: add memcg kmem_cache test Make a kasan test which uses a SLAB_ACCOUNT slab cache. If the test is run within a non default memcg, then it uncovers the bug fixed by "kasan: drain quarantine of memcg slab objects"[1]. If run without fix [1] it shows "Slab cache still has objects", and the kmem_cache structure is leaked. Here's an unpatched kernel test: $ dmesg -c > /dev/null $ mkdir /sys/fs/cgroup/memory/test $ echo $$ > /sys/fs/cgroup/memory/test/tasks $ modprobe test_kasan 2> /dev/null $ dmesg | grep -B1 still [ 123.456789] kasan test: memcg_accounted_kmem_cache allocate memcg accounted object [ 124.456789] kmem_cache_destroy test_cache: Slab cache still has objects Kernels with fix [1] don't have the "Slab cache still has objects" warning or the underlying leak. The new test runs and passes in the default (root) memcg, though in the root memcg it won't uncover the problem fixed by [1]. Link: http://lkml.kernel.org/r/1482257462-36948-2-git-send-email-gthelen@xxxxxxxxxx Signed-off-by: Greg Thelen <gthelen@xxxxxxxxxx> Reviewed-by: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_kasan.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff -puN lib/test_kasan.c~kasan-add-memcg-kmem_cache-test lib/test_kasan.c --- a/lib/test_kasan.c~kasan-add-memcg-kmem_cache-test +++ a/lib/test_kasan.c @@ -11,6 +11,7 @@ #define pr_fmt(fmt) "kasan test: %s " fmt, __func__ +#include <linux/delay.h> #include <linux/kernel.h> #include <linux/mman.h> #include <linux/mm.h> @@ -331,6 +332,38 @@ static noinline void __init kmem_cache_o kmem_cache_destroy(cache); } +static noinline void __init memcg_accounted_kmem_cache(void) +{ + int i; + char *p; + size_t size = 200; + struct kmem_cache *cache; + + cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL); + if (!cache) { + pr_err("Cache allocation failed\n"); + return; + } + + pr_info("allocate memcg accounted object\n"); + /* + * Several allocations with a delay to allow for lazy per memcg kmem + * cache creation. + */ + for (i = 0; i < 5; i++) { + p = kmem_cache_alloc(cache, GFP_KERNEL); + if (!p) { + pr_err("Allocation failed\n"); + goto free_cache; + } + kmem_cache_free(cache, p); + msleep(100); + } + +free_cache: + kmem_cache_destroy(cache); +} + static char global_array[10]; static noinline void __init kasan_global_oob(void) @@ -460,6 +493,7 @@ static int __init kmalloc_tests_init(voi kmalloc_uaf_memset(); kmalloc_uaf2(); kmem_cache_oob(); + memcg_accounted_kmem_cache(); kasan_stack_oob(); kasan_global_oob(); ksize_unpoisons_memory(); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
