lkml.org 
[lkml]   [2016]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH v4 2/2] kasan: add double-free tests
This patch adds new tests for KASAN double-free error detection when the
same slab object is concurrently deallocated.

Signed-off-by: Kuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
---

Changes in v4:
- There are *no* changes for v4.

Changes in v3:
- concurrent double-free test simplified to use on_each_cpu_mask() instead
of custom threads.
- reduced #threads and removed CONFIG_SMP guards per suggestion from Dmitry
Vyukov.

---

lib/test_kasan.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 5e51872..0f589e7 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -411,6 +411,49 @@ static noinline void __init copy_user_test(void)
kfree(kmem);
}

+#ifdef CONFIG_SLAB
+static void try_free(void *p)
+{
+ kfree(p);
+}
+
+static void __init kasan_double_free_concurrent(void)
+{
+#define MAX_THREADS 3
+ char *p;
+ int cpu, cnt = num_online_cpus();
+ cpumask_t mask = { CPU_BITS_NONE };
+ size_t size = 4097; /* must be <= KMALLOC_MAX_CACHE_SIZE/2 */
+
+ if (cnt == 1)
+ return;
+ cnt = cnt < MAX_THREADS ? cnt : MAX_THREADS;
+ pr_info("concurrent double-free (%d threads)\n", cnt);
+ p = kmalloc(size, GFP_KERNEL);
+ if (!p)
+ return;
+ for_each_online_cpu(cpu) {
+ cpumask_set_cpu(cpu, &mask);
+ if (!--cnt)
+ break;
+ }
+ on_each_cpu_mask(&mask, try_free, p, 0);
+}
+
+static noinline void __init kasan_double_free(void)
+{
+ char *p;
+ size_t size = 2049;
+
+ pr_info("double-free\n");
+ p = kmalloc(size, GFP_KERNEL);
+ if (!p)
+ return;
+ kfree(p);
+ kfree(p);
+}
+#endif
+
static int __init kmalloc_tests_init(void)
{
kmalloc_oob_right();
@@ -436,6 +479,10 @@ static int __init kmalloc_tests_init(void)
kasan_global_oob();
ksize_unpoisons_memory();
copy_user_test();
+#ifdef CONFIG_SLAB
+ kasan_double_free();
+ kasan_double_free_concurrent();
+#endif
return -EAGAIN;
}

--
1.7.1
\
 
 \ /
  Last update: 2016-05-29 18:41    [W:1.047 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site