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=ham 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 48FF8C43465 for ; Mon, 21 Sep 2020 14:41:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05FB523718 for ; Mon, 21 Sep 2020 14:41:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699301; bh=jhXXHiBwabz0eO6Y6MDYyI2GS5Y/LweyJRvHgKRcuMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1RMs1aqz6feQ61NXpK8C4mBQvNquukDG02eRPUaNfcB2Bsz51lKxMwbUgrL5h6xuh pq9aXXWKxL+NgpvNVTNV3rQy4SRNnHC6MPk26h9ur2oE/yZfYy/hWIqWOznjTQ6Fon tG96sFWramirMTESuOmz9Y3UYCSBApXEWumMJMQ0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728094AbgIUOlj (ORCPT ); Mon, 21 Sep 2020 10:41:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:50946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728061AbgIUOlc (ORCPT ); Mon, 21 Sep 2020 10:41:32 -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 C38D5221EC; Mon, 21 Sep 2020 14:41:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600699291; bh=jhXXHiBwabz0eO6Y6MDYyI2GS5Y/LweyJRvHgKRcuMc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dWYDI/qzirM7SgbvfjK745ncPh3d/BrNn96m8KNeX6J4CCGVnHZXagNAJ1x+GfSWm WAyWo0vJI5jCBaotlrz5SU4oPH+yEjAlBVFsbe6FokPGKKTqt8u8zs0lDKam0sfMsr bS8whiFmtucpUq0eicArQp5qEwaYG4JgVnT9PMbs= 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 4.14 3/3] objtool: Fix noreturn detection for ignored functions Date: Mon, 21 Sep 2020 10:41:27 -0400 Message-Id: <20200921144127.2135896-3-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200921144127.2135896-1-sashal@kernel.org> References: <20200921144127.2135896-1-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 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, -- 2.25.1