This is a note to let you know that I've just added the patch titled selftests/futex: pass _GNU_SOURCE without a value to the compiler to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: selftests-futex-pass-_gnu_source-without-a-value-to-.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ac531686745f5563e14fd2a4f4b9a327d9b9c9ca Author: John Hubbard <jhubbard@xxxxxxxxxx> Date: Tue May 28 19:29:38 2024 -0700 selftests/futex: pass _GNU_SOURCE without a value to the compiler [ Upstream commit cb708ab9f584f159798b60853edcf0c8b67ce295 ] It's slightly better to set _GNU_SOURCE in the source code, but if one must do it via the compiler invocation, then the best way to do so is this: $(CC) -D_GNU_SOURCE= ...because otherwise, if this form is used: $(CC) -D_GNU_SOURCE ...then that leads the compiler to set a value, as if you had passed in: $(CC) -D_GNU_SOURCE=1 That, in turn, leads to warnings under both gcc and clang, like this: futex_requeue_pi.c:20: warning: "_GNU_SOURCE" redefined Fix this by using the "-D_GNU_SOURCE=" form. Reviewed-by: Edward Liaw <edliaw@xxxxxxxxxx> Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile index a392d0917b4e5..994fa3468f170 100644 --- a/tools/testing/selftests/futex/functional/Makefile +++ b/tools/testing/selftests/futex/functional/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 INCLUDES := -I../include -I../../ $(KHDR_INCLUDES) -CFLAGS := $(CFLAGS) -g -O2 -Wall -D_GNU_SOURCE -pthread $(INCLUDES) $(KHDR_INCLUDES) +CFLAGS := $(CFLAGS) -g -O2 -Wall -D_GNU_SOURCE= -pthread $(INCLUDES) $(KHDR_INCLUDES) LDLIBS := -lpthread -lrt LOCAL_HDRS := \