From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752619AbcCIGIY (ORCPT ); Wed, 9 Mar 2016 01:08:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37726 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752407AbcCIGH5 (ORCPT ); Wed, 9 Mar 2016 01:07:57 -0500 From: Josh Poimboeuf To: Ingo Molnar Cc: Arnaldo Carvalho de Melo , Thomas Gleixner , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Michal Marek , Peter Zijlstra , Andy Lutomirski , Borislav Petkov , Linus Torvalds , Andi Kleen , Pedro Alves , Namhyung Kim , Bernd Petrovitsch , Chris J Arges , Andrew Morton , Jiri Slaby , Arnaldo Carvalho de Melo Subject: [PATCH 04/11] objtool: Fix false positive warnings related to sibling calls Date: Wed, 9 Mar 2016 00:06:54 -0600 Message-Id: <382de77ccaaa8cd79b27a155c3d109ebd4ce0219.1457502970.git.jpoimboe@redhat.com> In-Reply-To: References: <20160308154909.GA20956@gmail.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 09 Mar 2016 06:07:56 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With some configs [1], objtool prints a bunch of false positive warnings like: arch/x86/events/core.o: warning: objtool: x86_del_exclusive()+0x0: frame pointer state mismatch For some reason this config has a bunch of sibling calls. When objtool follows a sibling call jump, it attempts to compare the frame pointer state. But it also accidentally compares the FENTRY state, resulting in a false positive warning. [1] https://lkml.kernel.org/r/20160308154909.GA20956@gmail.com Signed-off-by: Josh Poimboeuf --- tools/objtool/builtin-check.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 51da270..fe24804 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -729,6 +729,11 @@ static bool has_valid_stack_frame(struct instruction *insn) (insn->state & STATE_FP_SETUP); } +static unsigned int frame_state(unsigned long state) +{ + return (state & (STATE_FP_SAVED | STATE_FP_SETUP)); +} + /* * Follow the branch starting at the given instruction, and recursively follow * any other branches (jumps). Meanwhile, track the frame pointer state at @@ -756,7 +761,7 @@ static int validate_branch(struct objtool_file *file, while (1) { if (insn->visited) { - if (insn->state != state) { + if (frame_state(insn->state) != frame_state(state)) { WARN_FUNC("frame pointer state mismatch", sec, insn->offset); warnings++; -- 2.4.3