Re: Unfortunate infinite make recursion

[Sam Ravnborg <sam@ravnborg.org>]

On Sat, Sep 22, 2007 at 01:24:32PM +0200, Jan Engelhardt wrote:
> Hi,
> 
> 
> 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!)
> 
> The make O=$PWD truncates the Makefile, making it necessary to run `git 
> checkout Makefile` - should you have git; or reextract the tarball 
> (should you /still/ have it). Well, can we catch this case somehow?

Does the following patch fix it at your end?
Seems to work for me.

	Sam

diff --git a/Makefile b/Makefile
index 6708e41..f787b05 100644
--- a/Makefile
+++ b/Makefile
@@ -115,7 +115,9 @@ saved-output := $(KBUILD_OUTPUT)
 KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd)
 $(if $(KBUILD_OUTPUT),, \
      $(error output directory "$(saved-output)" does not exist))
-
+# Check the OUTPUT directory is not the same as where we have kernel src
+$(if $(filter-out $(KBUILD_OUTPUT),$(shell /bin/pwd)),, \
+     $(error Output directory (O=...) specify kernel src dir))
 PHONY += $(MAKECMDGOALS)
 
 $(filter-out _all,$(MAKECMDGOALS)) _all: