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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 ECF7CC433E1 for ; Mon, 8 Jun 2020 23:49:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3CD4204EF for ; Mon, 8 Jun 2020 23:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591660153; bh=ZYWXVLDRpMx6fjTzG3pCvWzbfAZaCq5fQaiK1q3eva8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OmY1DkEiCh5ScX7xfFTHFSp5FCYu60xL8Tcy4TyRRtQWgrJgW90ZMOJFtzCkjqPau IPiJKUUF4dHmH166aYJ1H6Clu0oFldnFN3vmWhGrL4dpJTuOtT9KH+30e+ejSndd8W fRT4pt4hetj6wYW9iLFdTtVNaf+2C9OCoqRpWv9M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732533AbgFHXsq (ORCPT ); Mon, 8 Jun 2020 19:48:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:52390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730653AbgFHXZk (ORCPT ); Mon, 8 Jun 2020 19:25:40 -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 2BCE120812; Mon, 8 Jun 2020 23:25:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658740; bh=ZYWXVLDRpMx6fjTzG3pCvWzbfAZaCq5fQaiK1q3eva8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nkGnu3gf2GNlImuns0lCujV6FWp5RcWQZfDHvtxHdx0ViYAa0zxWbSfc0mPid3EFu m8swFQynVJWb8S3hj1jq+y5FqmA9CYh3lDFdEPnTFiVegSI6lN92cdQ+z3z4hGbxHc lFSbOiNZWgpmQR6BDGq098wKLYzbOran7zXjXxoM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kees Cook , Aaron Brown , Jeff Kirsher , Sasha Levin , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH AUTOSEL 4.14 27/72] e1000: Distribute switch variables for initialization Date: Mon, 8 Jun 2020 19:24:15 -0400 Message-Id: <20200608232500.3369581-27-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608232500.3369581-1-sashal@kernel.org> References: <20200608232500.3369581-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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 3dd4aeb2706d..175681aa5260 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -3169,8 +3169,9 @@ 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 @@ -3191,6 +3192,7 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb, } len = skb_headlen(skb); break; + } default: /* do nothing */ break; -- 2.25.1