On 04/05/2024 05:43, John Hubbard wrote: > When building with clang via: > > make LLVM=1 -C tools/testing/selftests > > two distinct failures occur: > > 1) 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/selftests > > However, 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. > > 2) clang won't accept invocations of this form, but gcc will: > > $(CC) file1.c header2.h > > Fix this by using selftests/lib.mk facilities for tracking local header > file dependencies: add them to LOCAL_HDRS, leaving only the .c files to > be passed to the compiler. > > Cc: Ryan Roberts <ryan.roberts@xxxxxxx> > Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> > --- > tools/testing/selftests/openat2/Makefile | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/tools/testing/selftests/openat2/Makefile b/tools/testing/selftests/openat2/Makefile > index 254d676a2689..185dc76ebb5f 100644 > --- a/tools/testing/selftests/openat2/Makefile > +++ b/tools/testing/selftests/openat2/Makefile > @@ -1,8 +1,18 @@ > # SPDX-License-Identifier: GPL-2.0-or-later > > -CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined -static-libasan > +CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined > TEST_GEN_PROGS := openat2_test resolve_test rename_attack_test > > +# gcc requires -static-libasan in order to ensure that Address Sanitizer's > +# library is the first one loaded. However, clang already statically links the > +# Address Sanitizer if -fsanitize is specified. Therefore, simply omit > +# -static-libasan for clang builds. > +ifeq ($(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@xxxxxxxxx/ [2] https://lore.kernel.org/linux-kselftest/20240417160740.2019530-1-ryan.roberts@xxxxxxx/ > + > +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
