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: 3203143f13
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221006171751.3444575-1-ndesaulniers@google.com
This commit is contained in:
Nick Desaulniers 2022-10-06 10:17:51 -07:00 committed by Kees Cook
parent 31970608a6
commit 0e5b9f25b2

View File

@ -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),