From patchwork Fri Feb 5 14:08:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 378042 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=-24.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, 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 7F98FC433DB for ; Fri, 5 Feb 2021 22:06:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EC1864DD6 for ; Fri, 5 Feb 2021 22:06:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233109AbhBEWFl (ORCPT ); Fri, 5 Feb 2021 17:05:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:45252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232941AbhBEO5X (ORCPT ); Fri, 5 Feb 2021 09:57:23 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 41364650B7; Fri, 5 Feb 2021 14:14:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612534475; bh=C8ZbliidtWdLrQu2YqsKNvIB9f+KJX3XYeJa+/oUWqg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2ZlCcYlznZ+cvXOJpS3/mzjJT5/oAJVVYgjF0iQLA6KYc0aU6uJMHpzZMcYG4D6Vz NKQ9AlYfKQIrzPO7+AscSzCxaVhD7Y5Zv3bb4bV2ksl3JgObpq4lF9bFmKwet+BUiC x/3H85EbdptlOSq6VCsZLz6zWDsk17bDJesJYbS0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Chancellor , Miroslav Benes , Josh Poimboeuf , Sasha Levin Subject: [PATCH 4.14 14/15] objtool: Dont fail on missing symbol table Date: Fri, 5 Feb 2021 15:08:59 +0100 Message-Id: <20210205140650.308445732@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210205140649.733510103@linuxfoundation.org> References: <20210205140649.733510103@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 1d489151e9f9d1647110277ff77282fe4d96d09b ] Thanks to a recent binutils change which doesn't generate unused symbols, it's now possible for thunk_64.o be completely empty without CONFIG_PREEMPTION: no text, no data, no symbols. We could edit the Makefile to only build that file when CONFIG_PREEMPTION is enabled, but that will likely create confusion if/when the thunks end up getting used by some other code again. Just ignore it and move on. Reported-by: Nathan Chancellor Reviewed-by: Nathan Chancellor Reviewed-by: Miroslav Benes Tested-by: Nathan Chancellor Link: https://github.com/ClangBuiltLinux/linux/issues/1254 Signed-off-by: Josh Poimboeuf Signed-off-by: Sasha Levin --- tools/objtool/elf.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index d089c711355a9..fa269622a974e 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -226,8 +226,11 @@ static int read_symbols(struct elf *elf) symtab = find_section_by_name(elf, ".symtab"); if (!symtab) { - WARN("missing symbol table"); - return -1; + /* + * A missing symbol table is actually possible if it's an empty + * .o file. This can happen for thunk_64.o. + */ + return 0; } symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;