When HEADER_ARCH was introduced, the MRPROPER_FILES (then MRPROPER_DIRS)
list wasn't adjusted, leaving SUBARCH as part of the path argument.
This resulted in the "mrproper" target not cleaning up arch/x86/... when
SUBARCH was specified. Since HOST_DIR is arch/$(HEADER_ARCH), use it
instead to get the correct path.

Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Azeem Shaikh <azeemshaikh38@gmail.com>
Cc: linux-um@lists.infradead.org
Fixes: 7bbe7204e937 ("um: merge Makefile-{i386,x86_64}")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/um/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/Makefile b/arch/um/Makefile
index 8186d4761bda..da4d5256af2f 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -149,7 +149,7 @@ export CFLAGS_vmlinux := $(LINK-y) $(LINK_WRAPS) $(LD_FLAGS_CMDLINE) $(CC_FLAGS_
 # When cleaning we don't include .config, so we don't include
 # TT or skas makefiles and don't clean skas_ptregs.h.
 CLEAN_FILES += linux x.i gmon.out
-MRPROPER_FILES += arch/$(SUBARCH)/include/generated
+MRPROPER_FILES += $(HOST_DIR)/include/generated
 
 archclean:
 	@find . \( -name '*.bb' -o -name '*.bbg' -o -name '*.da' \
-- 
2.34.1

On Tue, 6 Jun 2023 15:24:45 -0700, Kees Cook wrote:
> When HEADER_ARCH was introduced, the MRPROPER_FILES (then MRPROPER_DIRS)
> list wasn't adjusted, leaving SUBARCH as part of the path argument.
> This resulted in the "mrproper" target not cleaning up arch/x86/... when
> SUBARCH was specified. Since HOST_DIR is arch/$(HEADER_ARCH), use it
> instead to get the correct path.
> 
> 
> [...]

Build tested with/with-out patch, and I can see "mrproper" target
correctly cleaning up now.

Applied to for-next/hardening, thanks!

[1/1] um: Use HOST_DIR for mrproper
      https://git.kernel.org/kees/c/48ad87a5be06

-- 
Kees Cook