kbuild: fix infinite make recursion
Jan Engelhardt <jengelh@computergmbh.de> reported:
You can cause a recursion in kbuild/make with the following:
make O=$PWD kernel/time.o
make mrproper
Of course no one would use O=$PWD (that's just the testcase),
but this happened too often:
/ws/linux/linux-2.6.23$ make O=/ws/linux/linux-2.6.23 kernel/time.o
(Oops - should have been O=/ws/linux/obj-2.6.23!)
Fixed by an explicit test for this case - we error
out if output directory and source directory are the same.
Tested-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/Makefile b/Makefile
index 2738966..1b0d84d 100644
--- a/Makefile
+++ b/Makefile
@@ -115,7 +115,9 @@
KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd)
$(if $(KBUILD_OUTPUT),, \
$(error output directory "$(saved-output)" does not exist))
-
+# Check that OUTPUT directory is not the same as where we have kernel src
+$(if $(filter-out $(KBUILD_OUTPUT),$(shell /bin/pwd)),, \
+ $(error Output directory (O=...) specifies kernel src dir))
PHONY += $(MAKECMDGOALS)
$(filter-out _all,$(MAKECMDGOALS)) _all: