From patchwork Fri Jun 19 14:32:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 223631 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 7AB28C433E0 for ; Fri, 19 Jun 2020 16:53:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EE8520786 for ; Fri, 19 Jun 2020 16:53:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592585605; bh=mzuK37tzlKYYvOKx1l1TylVbig963irabrL266gf2hU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PyaXn1/KQQ+G92wyHCUQpH+/aSZ81QrnVOOGKMyTbvgyHRP7kG96Mb3OdB1cjI8sv dOqcvOwY8uJCMSv0L4mH26yuASOHtbqVDJuO3SHXpDapoURyhRy7eY3pwT9tsJmsRd X0yNdaK7A63h2sj5TA5hI1uKqW6TVx5G8Mz6srbs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394124AbgFSQxN (ORCPT ); Fri, 19 Jun 2020 12:53:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:54400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387742AbgFSOhb (ORCPT ); Fri, 19 Jun 2020 10:37:31 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 40CE120CC7; Fri, 19 Jun 2020 14:37:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592577450; bh=mzuK37tzlKYYvOKx1l1TylVbig963irabrL266gf2hU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SEPTZK5Cp95SCCWLqAwDKlOGCN13LhAroKOZhFD+UeNyaeXFCDDLpo4d0yT79bO6u WBr0VcnvnFwIBV5hQyE1BROMkvVAe/gwLZ3ppzJV14OXppRrvO4rFGK/LKlOIUYRLn 0IIuXLazG1wN56aM5OrqXl0KETMVDqqv5kWoF+ZE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Aaron Brown , Jeff Kirsher , Sasha Levin Subject: [PATCH 4.4 055/101] e1000: Distribute switch variables for initialization Date: Fri, 19 Jun 2020 16:32:44 +0200 Message-Id: <20200619141616.934934676@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141614.001544111@linuxfoundation.org> References: <20200619141614.001544111@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kees Cook [ Upstream commit a34c7f5156654ebaf7eaace102938be7ff7036cb ] Variables declared in a switch statement before any case statements cannot be automatically initialized with compiler instrumentation (as they are not part of any execution flow). With GCC's proposed automatic stack variable initialization feature, this triggers a warning (and they don't get initialized). Clang's automatic stack variable initialization (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also doesn't initialize such variables[1]. Note that these warnings (or silent skipping) happen before the dead-store elimination optimization phase, so even when the automatic initializations are later elided in favor of direct initializations, the warnings remain. To avoid these problems, move such variables into the "case" where they're used or lift them up into the main function body. drivers/net/ethernet/intel/e1000/e1000_main.c: In function ‘e1000_xmit_frame’: drivers/net/ethernet/intel/e1000/e1000_main.c:3143:18: warning: statement will never be executed [-Wswitch-unreachable] 3143 | unsigned int pull_size; | ^~~~~~~~~ [1] https://bugs.llvm.org/show_bug.cgi?id=44916 Signed-off-by: Kees Cook Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/e1000/e1000_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c index 1f84f2fa459f..f958188207fd 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -3162,8 +3162,9 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb, hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb); if (skb->data_len && hdr_len == len) { switch (hw->mac_type) { + case e1000_82544: { unsigned int pull_size; - case e1000_82544: + /* Make sure we have room to chop off 4 bytes, * and that the end alignment will work out to * this hardware's requirements @@ -3184,6 +3185,7 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb, } len = skb_headlen(skb); break; + } default: /* do nothing */ break;