From patchwork Tue Sep 29 11:00:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 290789 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F351FC47425 for ; Tue, 29 Sep 2020 12:35:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C297208FE for ; Tue, 29 Sep 2020 12:35:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601382932; bh=jhXXHiBwabz0eO6Y6MDYyI2GS5Y/LweyJRvHgKRcuMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kg2VweposEYtvcqfj0kstcZ6rSZ+VqWRewnEi6dZA2nO34rB8bfhv6LbFb75GtqNo PnqkH+OEhpsEgu4sK+USQtqpxBGMfT39tteBJQi8vsd07EDSD7o5lE27UzBF283Bqf 5t3wqd8TEz8V4lPnczm5GSoSi8dnOUt+1quDnrGU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732782AbgI2MfT (ORCPT ); Tue, 29 Sep 2020 08:35:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:37338 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729586AbgI2LVO (ORCPT ); Tue, 29 Sep 2020 07:21:14 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C5F31239EE; Tue, 29 Sep 2020 11:18:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378338; bh=jhXXHiBwabz0eO6Y6MDYyI2GS5Y/LweyJRvHgKRcuMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g5OzaB51TwdtQyqqRArh9+Tkfz30O1pOKPZjbYNQrKdYZ9aHjWHPN4YPlpy373DCc tFaBVW8GbudG0CFI8LH0jNbUwqGnDqW8FNUI+zs2dnlTVtxid2oCLoUWKFYdnHCSeQ O9P/9TIyyAW30XJxDfcnWtwXpKtA9FyBFT4fSCqM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds , Josh Poimboeuf , Borislav Petkov , Sasha Levin Subject: [PATCH 4.14 145/166] objtool: Fix noreturn detection for ignored functions Date: Tue, 29 Sep 2020 13:00:57 +0200 Message-Id: <20200929105942.438280216@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105935.184737111@linuxfoundation.org> References: <20200929105935.184737111@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Josh Poimboeuf [ Upstream commit db6c6a0df840e3f52c84cc302cc1a08ba11a4416 ] When a function is annotated with STACK_FRAME_NON_STANDARD, objtool doesn't validate its code paths. It also skips sibling call detection within the function. But sibling call detection is actually needed for the case where the ignored function doesn't have any return instructions. Otherwise objtool naively marks the function as implicit static noreturn, which affects the reachability of its callers, resulting in "unreachable instruction" warnings. Fix it by just enabling sibling call detection for ignored functions. The 'insn->ignore' check in add_jump_destinations() is no longer needed after e6da9567959e ("objtool: Don't use ignore flag for fake jumps"). Fixes the following warning: arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x142: unreachable instruction which triggers on an allmodconfig with CONFIG_GCOV_KERNEL unset. Reported-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Acked-by: Linus Torvalds Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin --- tools/objtool/check.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 247fbb5f6a389..2c8e2dae17016 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -502,7 +502,7 @@ static int add_jump_destinations(struct objtool_file *file) insn->type != INSN_JUMP_UNCONDITIONAL) continue; - if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET) + if (insn->offset == FAKE_JUMP_OFFSET) continue; rela = find_rela_by_dest_range(insn->sec, insn->offset,