On 04/05/2024 05:43, John Hubbard wrote:
When building with clang via:
make LLVM=1 -C tools/testing/selfteststwo distinct failures occur:
- gcc requires -static-libasan in order to ensure that Address
Sanitizer's library is the first one loaded. However, this leads to build failures on clang, when building via:
make LLVM=1 -C tools/testing/selftestsHowever, clang already does the right thing by default: it statically links the Address Sanitizer if -fsanitize is specified. Therefore, fix this by simply omitting -static-libasan for clang builds. And leave behind a comment, because the whole reason for static linking might not be obvious.
clang won't accept invocations of this form, but gcc will:
$(CC) file1.c header2.h
Fix this by using selftests/lib.mk facilities for tracking local header file dependencies: add them to LOCAL_HDRS, leaving only the .c files to be passed to the compiler.
Cc: Ryan Roberts ryan.roberts@arm.com Signed-off-by: John Hubbard jhubbard@nvidia.com
tools/testing/selftests/openat2/Makefile | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/openat2/Makefile b/tools/testing/selftests/openat2/Makefile index 254d676a2689..185dc76ebb5f 100644 --- a/tools/testing/selftests/openat2/Makefile +++ b/tools/testing/selftests/openat2/Makefile @@ -1,8 +1,18 @@ # SPDX-License-Identifier: GPL-2.0-or-later -CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined -static-libasan +CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined TEST_GEN_PROGS := openat2_test resolve_test rename_attack_test +# gcc requires -static-libasan in order to ensure that Address Sanitizer's +# library is the first one loaded. However, clang already statically links the +# Address Sanitizer if -fsanitize is specified. Therefore, simply omit +# -static-libasan for clang builds. +ifeq ($(LLVM),)
- CFLAGS += -static-libasan
+endif
It just occured to me that the bug report I was fixing with my attempt was invoking make like this (see [1]):
# tools/testing/selftests/fchmodat2$ make CC=clang # tools/testing/selftests/openat2$ make CC=clang
So LLVM is not set in this case. Perhaps my approach [2] (suggested by Arnd) of using cc-option is more robust? (cc-option is alredy used by other selftests).
[1] https://lore.kernel.org/all/202404141807.LgsqXPY5-lkp@intel.com/ [2] https://lore.kernel.org/linux-kselftest/20240417160740.2019530-1-ryan.robert...
+LOCAL_HDRS += helpers.h
include ../lib.mk -$(TEST_GEN_PROGS): helpers.c helpers.h +$(TEST_GEN_PROGS): helpers.c
base-commit: ddb4c3f25b7b95df3d6932db0b379d768a6ebdf7 prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27