From: Kees Cook keescook@chromium.org
[ Upstream commit 6a022dd29f2cefbac4895a34e2e1f14b2d12d819 ]
The 64-bit overflow tests will trigger 64-bit division on 32-bit hosts, which is not currently used anywhere in the kernel, and tickles bugs in at least Clang 13 and earlier: https://github.com/ClangBuiltLinux/linux/issues/1636
In reality, there shouldn't be a reason to not build the 64-bit test cases on 32-bit systems, so these #ifdefs can be removed once the minimum Clang version reaches 13.
In the meantime, silence W=1 warnings given by the current code:
../lib/overflow_kunit.c:191:19: warning: 's64_tests' defined but not used [-Wunused-const-variable=] 191 | DEFINE_TEST_ARRAY(s64) = { | ^~~ ../lib/overflow_kunit.c:24:11: note: in definition of macro 'DEFINE_TEST_ARRAY' 24 | } t ## _tests[] | ^ ../lib/overflow_kunit.c:94:19: warning: 'u64_tests' defined but not used [-Wunused-const-variable=] 94 | DEFINE_TEST_ARRAY(u64) = { | ^~~ ../lib/overflow_kunit.c:24:11: note: in definition of macro 'DEFINE_TEST_ARRAY' 24 | } t ## _tests[] | ^
Reported-by: kernel test robot lkp@intel.com Link: https://lore.kernel.org/lkml/202205110324.7GrtxG8u-lkp@intel.com Fixes: 455a35a6cdb6 ("lib: add runtime test of check_*_overflow functions") Cc: Rasmus Villemoes linux@rasmusvillemoes.dk Cc: Nick Desaulniers ndesaulniers@google.com Cc: Vitor Massaru Iha vitor@massaru.org Cc: "Gustavo A. R. Silva" gustavoars@kernel.org Tested-by: Daniel Latypov dlatypov@google.com Link: https://lore.kernel.org/lkml/CAGS_qxokQAjQRip2vPi80toW7hmBnXf=KMTNT51B1wuDqS... Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- lib/overflow_kunit.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c index 475f0c064bf6..7e3e43679b73 100644 --- a/lib/overflow_kunit.c +++ b/lib/overflow_kunit.c @@ -91,6 +91,7 @@ DEFINE_TEST_ARRAY(u32) = { {-4U, 5U, 1U, -9U, -20U, true, false, true}, };
+#if BITS_PER_LONG == 64 DEFINE_TEST_ARRAY(u64) = { {0, 0, 0, 0, 0, false, false, false}, {1, 1, 2, 0, 1, false, false, false}, @@ -114,6 +115,7 @@ DEFINE_TEST_ARRAY(u64) = { false, true, false}, {-15ULL, 10ULL, -5ULL, -25ULL, -150ULL, false, false, true}, }; +#endif
DEFINE_TEST_ARRAY(s8) = { {0, 0, 0, 0, 0, false, false, false}, @@ -188,6 +190,8 @@ DEFINE_TEST_ARRAY(s32) = { {S32_MIN, S32_MIN, 0, 0, 0, true, false, true}, {S32_MAX, S32_MAX, -2, 0, 1, true, false, true}, }; + +#if BITS_PER_LONG == 64 DEFINE_TEST_ARRAY(s64) = { {0, 0, 0, 0, 0, false, false, false},
@@ -216,6 +220,7 @@ DEFINE_TEST_ARRAY(s64) = { {-128, -1, -129, -127, 128, false, false, false}, {0, -S64_MAX, -S64_MAX, S64_MAX, 0, false, false, false}, }; +#endif
#define check_one_op(t, fmt, op, sym, a, b, r, of) do { \ t _r; \ @@ -650,6 +655,7 @@ static struct kunit_case overflow_test_cases[] = { KUNIT_CASE(s16_overflow_test), KUNIT_CASE(u32_overflow_test), KUNIT_CASE(s32_overflow_test), +/* Clang 13 and earlier generate unwanted libcalls on 32-bit. */ #if BITS_PER_LONG == 64 KUNIT_CASE(u64_overflow_test), KUNIT_CASE(s64_overflow_test),