Re: [PATCH v2 1/5] selftests: Compile kselftest headers with -D_GNU_SOURCE

[John Hubbard <jhubbard@xxxxxxxxxx>]

On 5/7/24 2:38 PM, Edward Liaw wrote:
> Add the -D_GNU_SOURCE flag to KHDR_INCLUDES so that it is defined in a
> central location.
>
> 809216233555 ("selftests/harness: remove use of LINE_MAX") introduced
> asprintf into kselftest_harness.h, which is a GNU extension and needs
> _GNU_SOURCE to either be defined prior to including headers or with the
> -D_GNU_SOURCE flag passed to the compiler.
>
> Fixes: 809216233555 ("selftests/harness: remove use of LINE_MAX")
> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-lkp/202404301040.3bea5782-oliver.sang@xxxxxxxxx
> Signed-off-by: Edward Liaw <edliaw@xxxxxxxxxx>
> ---
>   tools/testing/selftests/Makefile            | 4 ++--
>   tools/testing/selftests/kselftest_harness.h | 2 +-
>   tools/testing/selftests/lib.mk              | 2 +-
>   3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
> index e1504833654d..ed012a7f0786 100644
> --- a/tools/testing/selftests/Makefile
> +++ b/tools/testing/selftests/Makefile
> @@ -161,11 +161,11 @@ ifneq ($(KBUILD_OUTPUT),)
>     # $(realpath ...) resolves symlinks
>     abs_objtree := $(realpath $(abs_objtree))
>     BUILD := $(abs_objtree)/kselftest
> -  KHDR_INCLUDES := -isystem ${abs_objtree}/usr/include
> +  KHDR_INCLUDES := -D_GNU_SOURCE -isystem ${abs_objtree}/usr/include
>   else
>     BUILD := $(CURDIR)
>     abs_srctree := $(shell cd $(top_srcdir) && pwd)
> -  KHDR_INCLUDES := -isystem ${abs_srctree}/usr/include
> +  KHDR_INCLUDES := -D_GNU_SOURCE -isystem ${abs_srctree}/usr/include
>     DEFAULT_INSTALL_HDR_PATH := 1
>   endif

Just a small copy-paste duplication request: can we maybe do it this
way, instead, to remove the duplication? It's small *so far*, but
still. :)

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index e1504833654d..13a5b11db59a 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -152,6 +152,8 @@ ifeq ("$(origin O)", "command line")
   KBUILD_OUTPUT := $(O)
 endif
 
+KHDR_INCLUDES := -D_GNU_SOURCE
+
 ifneq ($(KBUILD_OUTPUT),)
   # Make's built-in functions such as $(abspath ...), $(realpath ...) cannot
   # expand a shell special character '~'. We use a somewhat tedious way here.
@@ -161,11 +163,11 @@ ifneq ($(KBUILD_OUTPUT),)
   # $(realpath ...) resolves symlinks
   abs_objtree := $(realpath $(abs_objtree))
   BUILD := $(abs_objtree)/kselftest
-  KHDR_INCLUDES := -isystem ${abs_objtree}/usr/include
+  KHDR_INCLUDES += -isystem ${abs_objtree}/usr/include
 else
   BUILD := $(CURDIR)
   abs_srctree := $(shell cd $(top_srcdir) && pwd)
-  KHDR_INCLUDES := -isystem ${abs_srctree}/usr/include
+  KHDR_INCLUDES += -isystem ${abs_srctree}/usr/include
   DEFAULT_INSTALL_HDR_PATH := 1
 endif


>   
> diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
> index d98702b6955d..b2a1b6343896 100644
> --- a/tools/testing/selftests/kselftest_harness.h
> +++ b/tools/testing/selftests/kselftest_harness.h
> @@ -51,7 +51,7 @@
>   #define __KSELFTEST_HARNESS_H
>   
>   #ifndef _GNU_SOURCE
> -#define _GNU_SOURCE
> +static_assert(0, "kselftest harness requires _GNU_SOURCE to be defined");
>   #endif
>   #include <asm/types.h>
>   #include <ctype.h>
> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
> index da2cade3bab0..2503dc732b4d 100644
> --- a/tools/testing/selftests/lib.mk
> +++ b/tools/testing/selftests/lib.mk
> @@ -45,7 +45,7 @@ selfdir = $(realpath $(dir $(filter %/lib.mk,$(MAKEFILE_LIST))))
>   top_srcdir = $(selfdir)/../../..
>   
>   ifeq ($(KHDR_INCLUDES),)
> -KHDR_INCLUDES := -isystem $(top_srcdir)/usr/include
> +KHDR_INCLUDES := -D_GNU_SOURCE -isystem $(top_srcdir)/usr/include
>   endif
>   
>   # The following are built by lib.mk common compile rules.

The rest looks good. And whether you accept my recommendation above,
or not, either way this patch looks good, so please feel free to add:

Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>


thanks,
--
John Hubbard
NVIDIA