+ kasan-initialise-array-in-kasan_memcmp-test.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: kasan: initialise array in kasan_memcmp test
has been added to the -mm tree.  Its filename is
     kasan-initialise-array-in-kasan_memcmp-test.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/kasan-initialise-array-in-kasan_memcmp-test.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/kasan-initialise-array-in-kasan_memcmp-test.patch

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------------------------------------------------------
From: Daniel Axtens <dja@axtens.net>
Subject: kasan: initialise array in kasan_memcmp test

memcmp may bail out before accessing all the memory if the buffers contain
differing bytes.  kasan_memcmp calls memcmp with a stack array.  Stack
variables are not necessarily initialised (in the absence of a compiler
plugin, at least).  Sometimes this causes the memcpy to bail early thus
fail to trigger kasan.

Make sure the array initialised to zero in the code.

No other test is dependent on the contents of an array on the stack.

Link: http://lkml.kernel.org/r/20200423154503.5103-4-dja@axtens.net
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/test_kasan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/lib/test_kasan.c~kasan-initialise-array-in-kasan_memcmp-test
+++ a/lib/test_kasan.c
@@ -638,7 +638,7 @@ static noinline void __init kasan_memcmp
 {
 	char *ptr;
 	size_t size = 24;
-	int arr[9];
+	int arr[9] = {};
 
 	pr_info("out-of-bounds in memcmp\n");
 	ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
_

Patches currently in -mm which might be from dja@axtens.net are

kasan-stop-tests-being-eliminated-as-dead-code-with-fortify_source.patch
stringh-fix-incompatibility-between-fortify_source-and-kasan.patch
kasan-initialise-array-in-kasan_memcmp-test.patch