From: Yury Norov yury.norov@gmail.com
[ Upstream commit 2356d198d2b4ddec24efea98271cb3be230bc787 ]
When building with Clang, and when KASAN and GCOV_PROFILE_ALL are both enabled, the test fails to build [1]:
lib/test_bitmap.c:920:2: error: call to '__compiletime_assert_239' declared with 'error' attribute: BUILD_BUG_ON failed: !__builtin_constant_p(res)
BUILD_BUG_ON(!__builtin_constant_p(res)); ^ include/linux/build_bug.h:50:2: note: expanded from macro 'BUILD_BUG_ON' BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) ^ include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG' #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^ include/linux/compiler_types.h:352:2: note: expanded from macro 'compiletime_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) ^ include/linux/compiler_types.h:340:2: note: expanded from macro '_compiletime_assert' __compiletime_assert(condition, msg, prefix, suffix) ^ include/linux/compiler_types.h:333:4: note: expanded from macro '__compiletime_assert' prefix ## suffix(); \ ^ <scratch space>:185:1: note: expanded from here __compiletime_assert_239
Originally it was attributed to s390, which now looks seemingly wrong. The issue is not related to bitmap code itself, but it breaks build for a given configuration.
Disabling the const_eval test under that config may potentially hide other bugs. Instead, workaround it by disabling GCOV for the test_bitmap unless the compiler will get fixed.
[1] https://github.com/ClangBuiltLinux/linux/issues/1874
Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202307171254.yFcH97ej-lkp@intel.com/ Fixes: dc34d5036692 ("lib: test_bitmap: add compile-time optimization/evaluations assertions") Co-developed-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Yury Norov yury.norov@gmail.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Reviewed-by: Alexander Lobakin aleksander.lobakin@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- lib/Makefile | 6 ++++++ lib/test_bitmap.c | 8 ++++---- 2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/lib/Makefile b/lib/Makefile index 876fcdeae34ec..05d8ec332baac 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -82,7 +82,13 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o obj-$(CONFIG_TEST_PRINTF) += test_printf.o obj-$(CONFIG_TEST_SCANF) += test_scanf.o + obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o +ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_KASAN),yy) +# FIXME: Clang breaks test_bitmap_const_eval when KASAN and GCOV are enabled +GCOV_PROFILE_test_bitmap.o := n +endif + obj-$(CONFIG_TEST_UUID) += test_uuid.o obj-$(CONFIG_TEST_XARRAY) += test_xarray.o obj-$(CONFIG_TEST_MAPLE_TREE) += test_maple_tree.o diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index a8005ad3bd589..37a9108c4f588 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -1149,6 +1149,10 @@ static void __init test_bitmap_print_buf(void) } }
+/* + * FIXME: Clang breaks compile-time evaluations when KASAN and GCOV are enabled. + * To workaround it, GCOV is force-disabled in Makefile for this configuration. + */ static void __init test_bitmap_const_eval(void) { DECLARE_BITMAP(bitmap, BITS_PER_LONG); @@ -1174,11 +1178,7 @@ static void __init test_bitmap_const_eval(void) * the compiler is fixed. */ bitmap_clear(bitmap, 0, BITS_PER_LONG); -#if defined(__s390__) && defined(__clang__) - if (!const_test_bit(7, bitmap)) -#else if (!test_bit(7, bitmap)) -#endif bitmap_set(bitmap, 5, 2);
/* Equals to `unsigned long bitopvar = BIT(20)` */