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=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 83163C433E4 for ; Mon, 8 Jun 2020 23:43:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A70220659 for ; Mon, 8 Jun 2020 23:43:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591659831; bh=5Je26gO6C3CocQCMRXvtb19WLm+OtkVowkKyukTrP44=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kQ4n6ItT3wOdx2WR09RVOXX1jEdtpyMYYAtL3Bjbv3bRpUW1oWynzOeUxuavHpIiY Tqte356hQFa8iFwLwhYdeYglrlCcBywNyrsXFIGHW/zKj4waRXQJ9IePh1ulJH+Avh jwxVuVuBGs384rl0JJZmMvm3nhA7UC2w3GQrSuB8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732409AbgFHXnu (ORCPT ); Mon, 8 Jun 2020 19:43:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:55188 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731712AbgFHX1H (ORCPT ); Mon, 8 Jun 2020 19:27:07 -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 9C23820853; Mon, 8 Jun 2020 23:27:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658826; bh=5Je26gO6C3CocQCMRXvtb19WLm+OtkVowkKyukTrP44=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s+OLnPjg0RrgajBOafGl0xk/aMuY27nrlS0bwr/kDM3moY+sdU2B9awktmW+S//ie 0nG7O1eWK1KOG6DLL33miHWRPKk3Yx8HdzA+/YCA4pkLysITWlc+nwDfq+rCHs7bmK oZsNKSrpXKKKzK51bgBRT+4O3BlCWmdTTd23dK+c= 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 4.9 18/50] e1000: Distribute switch variables for initialization Date: Mon, 8 Jun 2020 19:26:08 -0400 Message-Id: <20200608232640.3370262-18-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608232640.3370262-1-sashal@kernel.org> References: <20200608232640.3370262-1-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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 39a09e18c1b7..3b16ee0de246 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -3167,8 +3167,9 @@ 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 @@ -3189,6 +3190,7 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb, } len = skb_headlen(skb); break; + } default: /* do nothing */ break; -- 2.25.1