From patchwork Tue Sep 29 11:01:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 290865 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 17D7EC4741F for ; Tue, 29 Sep 2020 12:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD6062083B for ; Tue, 29 Sep 2020 12:21:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601382071; bh=UmfOEWYj34C5ffDav60qdmjst3axFRRXhD0Ky0DqY8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PudsK+jYVAOp3yo0KeJJqjEsa3YulRfQxE5+hVi+qUp4ndZ5+qsv/XqjqERgTvOWm WvZHTHJJ2c+6XXmfGXBbieeV8Tlk9Bm3jYAaHi/5yHQAd6cR2DRg9ScA51/SCGjpJQ sriSy698SdvJgNQDz3ympyrtsugxVdByAllcUHiw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732295AbgI2MUz (ORCPT ); Tue, 29 Sep 2020 08:20:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:50310 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729851AbgI2Lfe (ORCPT ); Tue, 29 Sep 2020 07:35:34 -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 3CE0A23D4F; Tue, 29 Sep 2020 11:29:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378990; bh=UmfOEWYj34C5ffDav60qdmjst3axFRRXhD0Ky0DqY8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zXEHZK4OeApTR2GN4VbZraoN4Y0UgjPD/CuaFpY8pkDI/1ZPPX/Gs3HkMXhceuQMn Ugpuic8n0U4eclnK6hnax3UnkIhJCny6X8oqJVEykqpPvhQSIoyXKjYgQ5NQ8DzKyS vaOZiTiQYo6rt1PLb4nN1Roc+D5h9yB4SIgzXMhA= 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 4.19 214/245] objtool: Fix noreturn detection for ignored functions Date: Tue, 29 Sep 2020 13:01:05 +0200 Message-Id: <20200929105957.390557114@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105946.978650816@linuxfoundation.org> References: <20200929105946.978650816@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 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,