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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Valdis Kletnieks <valdis.kletnieks@vt.edu>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH 5.2 29/45] objtool: Clobber user CFLAGS variable
Date:   Sun, 29 Sep 2019 15:55:57 +0200
Message-Id: <20190929135031.833990464@linuxfoundation.org>
In-Reply-To: <20190929135024.387033930@linuxfoundation.org>
References: <20190929135024.387033930@linuxfoundation.org>
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From: Josh Poimboeuf <jpoimboe@redhat.com>

commit f73b3cc39c84220e6dccd463b5c8279b03514646 upstream.

If the build user has the CFLAGS variable set in their environment,
objtool blindly appends to it, which can cause unexpected behavior.

Clobber CFLAGS to ensure consistent objtool compilation behavior.

Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/83a276df209962e6058fcb6c615eef9d401c21bc.1567121311.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
CC: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/objtool/Makefile |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -35,7 +35,7 @@ INCLUDES := -I$(srctree)/tools/include \
 	    -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
 	    -I$(srctree)/tools/objtool/arch/$(ARCH)/include
 WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
-CFLAGS   += -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBELF_FLAGS)
+CFLAGS   := -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBELF_FLAGS)
 LDFLAGS  += $(LIBELF_LIBS) $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)
 
 # Allow old libelf to be used: