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: > > $(CC) file1.c header2.h > > Fix this by using selftests/lib.mk facilities for tracking local header > file dependencies: add them to LOCAL_HDRS, leaving only the .c files to > be passed to the compiler. > > Cc: Ryan Roberts <[email protected]> > Signed-off-by: John Hubbard <[email protected]>
Hi John, I sent out a similar fix a couple of weeks ago, see [1]. I don't think it got picked up though. It takes a slightly different approach, explicitly adding -static-libsan (note no 'a') for clang, instead of relying on its default. And it just drops helpers.h from the makefile altogether, on the assumption that it was a mistake; its just a header and shouldn't be compiled directly. I'm not exactly sure what the benefit of adding it to LOCAL_HDRS is? [1] https://lore.kernel.org/linux-kselftest/[email protected]/ Thanks, Ryan > --- > tools/testing/selftests/openat2/Makefile | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/tools/testing/selftests/openat2/Makefile > b/tools/testing/selftests/openat2/Makefile > index 254d676a2689..185dc76ebb5f 100644 > --- a/tools/testing/selftests/openat2/Makefile > +++ b/tools/testing/selftests/openat2/Makefile > @@ -1,8 +1,18 @@ > # SPDX-License-Identifier: GPL-2.0-or-later > > -CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined > -static-libasan > +CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined > TEST_GEN_PROGS := openat2_test resolve_test rename_attack_test > > +# gcc requires -static-libasan in order to ensure that Address Sanitizer's > +# library is the first one loaded. However, clang already statically links > the > +# Address Sanitizer if -fsanitize is specified. Therefore, simply omit > +# -static-libasan for clang builds. > +ifeq ($(LLVM),) > + CFLAGS += -static-libasan > +endif > + > +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
