From mboxrd@z Thu Jan 1 00:00:00 1970 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=-14.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 CA768C43465 for ; Mon, 21 Sep 2020 14:42:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89F22221EC for ; Mon, 21 Sep 2020 14:42:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699334; bh=UmfOEWYj34C5ffDav60qdmjst3axFRRXhD0Ky0DqY8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=u6V+3dovnuD91wY1Xqui3ixAh5wkjwsI9pJQxHbie558uza5cWj5Q8vQy4bnydFEH JDuTNQrZMiGPgp7gbUV4+nQ7dB2EcS7Mk/v6TNt+yhFSRwY3Ghj/xyMMA+YfXnU86r YrTatTTqC+hLgsBFs4V8Te9ZEU/5kOBszeQIwBHM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728144AbgIUOmN (ORCPT ); Mon, 21 Sep 2020 10:42:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:50786 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728040AbgIUOl1 (ORCPT ); Mon, 21 Sep 2020 10:41:27 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CBFC7235F8; Mon, 21 Sep 2020 14:41:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699286; bh=UmfOEWYj34C5ffDav60qdmjst3axFRRXhD0Ky0DqY8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PZUZDi/C53GryhiD4RIs9lTme8uke/ggpt6CTBZLwM/dBSuvdAbmgA7ZaZN+tWGo8 H4bftoq6gbeBeSX8Ovn/7XXCJhRf9Aa5UNEgjAKSk2yEuShG9teYYUqY4HUcnzneRC coyKIsdMzjUyErcSOn6LLPZv/LAkiXYZFEOlc+cc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Josh Poimboeuf , Linus Torvalds , Borislav Petkov , Sasha Levin Subject: [PATCH AUTOSEL 4.19 9/9] objtool: Fix noreturn detection for ignored functions Date: Mon, 21 Sep 2020 10:41:14 -0400 Message-Id: <20200921144114.2135773-9-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200921144114.2135773-1-sashal@kernel.org> References: <20200921144114.2135773-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 fd3071d83deae..c0ab27368a345 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -503,7 +503,7 @@ 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, -- 2.25.1