Commit 0e5b9f25 authored by Nick Desaulniers's avatar Nick Desaulniers Committed by Kees Cook
Browse files

overflow: disable failing tests for older clang versions 

Building the overflow kunit tests with clang-11 fails with:

$ ./tools/testing/kunit/kunit.py run --arch=arm --make_options LLVM=1 \
overflow
...
ld.lld: error: undefined symbol: __mulodi4
...

Clang 11 and earlier generate unwanted libcalls for signed output,
unsigned input.

Disable these tests for now, but should these become used in the kernel
we might consider that as justification for dropping clang-11 support.
Keep the clang-11 build alive a little bit longer.

Avoid -Wunused-function warnings via __maybe_unused. To test W=1:

$ make LLVM=1 -j128 defconfig
$ ./scripts/config -e KUNIT -e KUNIT_ALL
$ make LLVM=1 -j128 olddefconfig lib/overflow_kunit.o W=1

Link: https://github.com/ClangBuiltLinux/linux/issues/1711
Link: https://github.com/llvm/llvm-project/commit/3203143f1356a4e4e3ada231156fc6da6e1a9f9d


Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221006171751.3444575-1-ndesaulniers@google.com
parent 31970608

lib/overflow_kunit.c

+8 −1
Original line number Diff line number Diff line
@@ -254,6 +254,7 @@ static void do_test_ ## n(struct kunit *test, const struct test_ ## n *p) \ 
	check_one_op(t, fmt, mul, "*", p->b, p->a, p->prod, p->p_of);	\

}									\

									\

__maybe_unused								\

static void n ## _overflow_test(struct kunit *test) {			\

	unsigned i;							\

									\
@@ -720,8 +721,14 @@ static struct kunit_case overflow_test_cases[] = { 
	KUNIT_CASE(u64_u64__u64_overflow_test),

	KUNIT_CASE(s64_s64__s64_overflow_test),

#endif

	KUNIT_CASE(u32_u32__u8_overflow_test),

/*

 * Clang 11 and earlier generate unwanted libcalls for signed output, unsigned

 * input.

 */

#if !(defined(CONFIG_CC_IS_CLANG) && __clang_major__ <= 11)

	KUNIT_CASE(u32_u32__int_overflow_test),

#endif

	KUNIT_CASE(u32_u32__u8_overflow_test),

	KUNIT_CASE(u8_u8__int_overflow_test),

	KUNIT_CASE(int_int__u8_overflow_test),

	KUNIT_CASE(shift_sane_test),