From 02a6e4be2ff44344f58b078c18dc3ab3877fcfe5 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 4 Apr 2022 15:19:42 +0900 Subject: kbuild: prevent exported headers from including , Some UAPI headers included , like this: #ifndef __KERNEL__ #include #endif As it turned out, they just included it for no good reason. After some fixes, now I can compile-test UAPI headers (CONFIG_UAPI_HEADER_TEST=y) without including from the system header search paths. To avoid somebody getting it back again, this commit adds the dummy header, usr/dummy-include/stdlib.h I added $(srctree)/usr/dummy-include to the header search paths. Because it is searched before the system directories, if someone tries to include , they will see the error message. While I am here, I also replaced $(objtree)/usr/include with $(obj), but it has no functional change. If we can make kernel headers self-contained (that is, none of exported kernel headers includes system headers), we will be able to add the -nostdinc flag, but that is much far from where we stand now. As a realistic solution, we can ban header inclusion individually by putting a dummy header into usr/dummy-include/. Currently, no header include . I put it as well before somebody attempts to use it. Signed-off-by: Masahiro Yamada Signed-off-by: Arnd Bergmann Reviewed-by: Greg Kroah-Hartman --- usr/dummy-include/stdlib.h | 7 +++++++ 1 file changed, 7 insertions(+) create mode 100644 usr/dummy-include/stdlib.h (limited to 'usr/dummy-include/stdlib.h') diff --git a/usr/dummy-include/stdlib.h b/usr/dummy-include/stdlib.h new file mode 100644 index 000000000000..e8c21888e371 --- /dev/null +++ b/usr/dummy-include/stdlib.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _STDLIB_H +#define _STDLIB_H + +#error "Please do not include from exported headers" + +#endif /* _STDLIB_H */ -- cgit v1.2.3