From patchwork Tue Sep 29 11:01:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 263199 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=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 AC1AAC4727C for ; Tue, 29 Sep 2020 11:53:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 637B3206A5 for ; Tue, 29 Sep 2020 11:53:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601380434; bh=puesQLL1vTui9u2CuuuBOVYfBiDNpon7FKU4BmliOZs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1pXGCbbeURTfGgpYyiKhz7Ag9PcFqxIUcVg+v4WxX64z6fbg6eeDYqJ8TNq5j8sU2 IydyXXBhkc7av8bnpaKJ2RI02PPmYvpQyD4eBFiJ7FkGXCDMbdLyGvjKpfIxIqkag2 RGTnAd9O1usbCh9nm8QgnCwwAyH1p+pEtIdc675M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731249AbgI2Lxx (ORCPT ); Tue, 29 Sep 2020 07:53:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730986AbgI2Lqh (ORCPT ); Tue, 29 Sep 2020 07:46:37 -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 B860620848; Tue, 29 Sep 2020 11:46:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379989; bh=puesQLL1vTui9u2CuuuBOVYfBiDNpon7FKU4BmliOZs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=stdF3KnU2vxiLNspN7g6keZ7R8ZGXrpINrUy0sVKwOu8z+6l1/qGCdwWF7y5WPV3a JlqRC0hLYerTO81xAFwZaUMr2XBINDQkLpUUPNr9xyPT0aUbOzaD2hRJb1Y3YzUi2p ZM7Gbc/dRwV7ND5OBYH67N3LoyX0ZEmySmGAjic4= 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 5.8 18/99] objtool: Fix noreturn detection for ignored functions Date: Tue, 29 Sep 2020 13:01:01 +0200 Message-Id: <20200929105930.615718036@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105929.719230296@linuxfoundation.org> References: <20200929105929.719230296@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 5e0d70a89fb87..773e6c7ee5f93 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -619,7 +619,7 @@ static int add_jump_destinations(struct objtool_file *file) if (!is_static_jump(insn)) continue; - if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET) + if (insn->offset == FAKE_JUMP_OFFSET) continue; rela = find_rela_by_dest_range(file->elf, insn->sec,