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
Unified · Split
| @@ -82,7 +82,13 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o · 81 unmodified lines | ||
| 82 | 82 | obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o |
| 83 | 83 | obj-$(CONFIG_TEST_PRINTF) += test_printf.o |
| 84 | 84 | obj-$(CONFIG_TEST_SCANF) += test_scanf.o |
| 85 | + | |
| 85 | 86 | obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o |
| 87 | +ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_KASAN),yy) | |
| 88 | +# FIXME: Clang breaks test_bitmap_const_eval when KASAN and GCOV are enabled | |
| 89 | +GCOV_PROFILE_test_bitmap.o := n | |
| 90 | +endif | |
| 91 | + | |
| 86 | 92 | obj-$(CONFIG_TEST_UUID) += test_uuid.o |
| 87 | 93 | obj-$(CONFIG_TEST_XARRAY) += test_xarray.o |
| 88 | 94 | obj-$(CONFIG_TEST_MAPLE_TREE) += test_maple_tree.o |
| @@ -1161,6 +1161,10 @@ static void __init test_bitmap_print_buf(void) · 1160 unmodified lines | ||
| 1161 | 1161 | } |
| 1162 | 1162 | } |
| 1163 | 1163 | |
| 1164 | +/* | |
| 1165 | + * FIXME: Clang breaks compile-time evaluations when KASAN and GCOV are enabled. | |
| 1166 | + * To workaround it, GCOV is force-disabled in Makefile for this configuration. | |
| 1167 | + */ | |
| 1164 | 1168 | static void __init test_bitmap_const_eval(void) |
| 1165 | 1169 | { |
| 1166 | 1170 | DECLARE_BITMAP(bitmap, BITS_PER_LONG); |
| @@ -1186,11 +1190,7 @@ static void __init test_bitmap_const_eval(void) · 19 unmodified lines | ||
| 1186 | 1190 | * the compiler is fixed. |
| 1187 | 1191 | */ |
| 1188 | 1192 | bitmap_clear(bitmap, 0, BITS_PER_LONG); |
| 1189 | −#if defined(__s390__) && defined(__clang__) | |
| 1190 | − if (!const_test_bit(7, bitmap)) | |
| 1191 | −#else | |
| 1192 | 1193 | if (!test_bit(7, bitmap)) |
| 1193 | −#endif | |
| 1194 | 1194 | bitmap_set(bitmap, 5, 2); |
| 1195 | 1195 | |
| 1196 | 1196 | /* Equals to `unsigned long bitopvar = BIT(20)` */ |