From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [net,2/2] net: i40e: shut up uninitialized variable warnings Date: Sun, 31 Jan 2016 15:59:17 +0100 Message-ID: <2154537.J75p8oY6mX@wuerfel> References: <1453766332-43274-3-git-send-email-jeffrey.t.kirsher@intel.com> <56ACD7C6.1010808@virtuozzo.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: Jeff Kirsher , davem@davemloft.net, netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com To: Vasily Averin Return-path: Received: from mout.kundenserver.de ([217.72.192.73]:56696 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757218AbcAaO7t (ORCPT ); Sun, 31 Jan 2016 09:59:49 -0500 In-Reply-To: <56ACD7C6.1010808@virtuozzo.com> Sender: netdev-owner@vger.kernel.org List-ID: On Saturday 30 January 2016 18:33:26 Vasily Averin wrote: > On 26.01.2016 02:58, Jeff Kirsher wrote: > > From: Arnd Bergmann > > > > intel/i40e/i40e_txrx.c: In function 'i40e_xmit_frame_ring': > > intel/i40e/i40e_txrx.c:2367:20: error: 'oiph' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > intel/i40e/i40e_txrx.c:2317:16: note: 'oiph' was declared here > > intel/i40e/i40e_txrx.c:2367:17: error: 'oudph' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > intel/i40e/i40e_txrx.c:2316:17: note: 'oudph' was declared here > > 2364 if ((tx_ring->flags & I40E_TXR_FLAGS_OUTER_UDP_CSUM) && > 2365 (l4_tunnel == I40E_TXD_CTX_UDP_TUNNELING) && > 2366 (*cd_tunneling & I40E_TXD_CTX_QW0_EXT_IP_MASK)) { > 2367 oudph->check = ~csum_tcpudp_magic(oiph->saddr, > 2368 oiph->daddr, > 2369 (skb->len - skb_transport_offset(skb)), > 2370 IPPROTO_UDP, 0); > > if compiler reports that oudph and oiph can be unitialized here, > it's not enough just to set them to NULL. > > Do we need probably to check that variables was initialized before access here? > i.e. add oudph && oiph into condition? Sorry, I should not have mentioned my patch when it wasn't meant as a serious submission. The patch I sent did not have a proper changelog on it so it failed to explain it. The reason why my patch works correctly is that the check on "l4_tunnel == I40E_TXD_CTX_UDP_TUNNELING" means we can only get here if the two variables have been initialized, and gcc fails to see this. Jeff mentioned that he already had a patch for this, so I did not follow up with a real patch. Arnd