The patch titled
Subject: kasan: fix -Wstringop-overflow warning
has been added to the -mm tree. Its filename is
kasan-fix-wstringop-overflow-warning.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-fix-wstringop-overflow-warning.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-fix-wstringop-overflow-warning.patch
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there every 3-4 working days
------------------------------------------------------
From: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Subject: kasan: fix -Wstringop-overflow warning
Compiling with gcc-9.2.1 points out below warnings.
In function 'memmove',
inlined from 'kmalloc_memmove_invalid_size' at lib/test_kasan.c:301:2:
include/linux/string.h:441:9: warning: '__builtin_memmove' specified
bound 18446744073709551614 exceeds maximum object size
9223372036854775807 [-Wstringop-overflow=]
Why generate this warning? Because our test function deliberately pass a
negative number in memmove(), so we need to make it "volatile" so that
compiler doesn't see it.
Link: http://lkml.kernel.org/r/20200311134244.13016-1-walter-zh.wu@xxxxxxxxxxxx
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_kasan.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/lib/test_kasan.c~kasan-fix-wstringop-overflow-warning
+++ a/lib/test_kasan.c
@@ -289,6 +289,7 @@ static noinline void __init kmalloc_memm
{
char *ptr;
size_t size = 64;
+ volatile size_t invalid_size = -2;
pr_info("invalid size in memmove\n");
ptr = kmalloc(size, GFP_KERNEL);
@@ -298,7 +299,7 @@ static noinline void __init kmalloc_memm
}
memset((char *)ptr, 0, 64);
- memmove((char *)ptr, (char *)ptr + 4, -2);
+ memmove((char *)ptr, (char *)ptr + 4, invalid_size);
kfree(ptr);
}
_
Patches currently in -mm which might be from walter-zh.wu@xxxxxxxxxxxx are
kasan-detect-negative-size-in-memory-operation-function.patch
kasan-add-test-for-invalid-size-in-memmove.patch
kasan-fix-wstringop-overflow-warning.patch
