From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 3DAD61B1F2 for ; Fri, 6 Oct 2017 02:18:01 +0200 (CEST) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Oct 2017 17:18:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,482,1500966000"; d="scan'208";a="907223994" Received: from unknown (HELO [10.241.225.33]) ([10.241.225.33]) by FMSMGA003.fm.intel.com with ESMTP; 05 Oct 2017 17:18:00 -0700 To: Olivier Matz , dev@dpdk.org, Bruce Richardson References: <20170911151333.5727-1-olivier.matz@6wind.com> <20170911151333.5727-9-olivier.matz@6wind.com> From: Ferruh Yigit Message-ID: <228abb94-4939-8425-9451-2fb57fd1c567@intel.com> Date: Fri, 6 Oct 2017 01:18:00 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20170911151333.5727-9-olivier.matz@6wind.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH 08/10] lpm6: fix compilation with -Og X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Oct 2017 00:18:02 -0000 On 9/11/2017 4:13 PM, Olivier Matz wrote: > The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following > error: > > CC rte_lpm6.o > rte_lpm6.c: In function ‘rte_lpm6_add_v1705’: > rte_lpm6.c:442:11: error: ‘tbl_next’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > if (!tbl[tbl_index].valid) { > ^ > rte_lpm6.c:521:29: note: ‘tbl_next’ was declared here > struct rte_lpm6_tbl_entry *tbl_next; > ^~~~~~~~ > > This is a false positive from gcc. Fix it by initializing tbl_next > to NULL. This is hard to trace, and it seems there is a way to have it, not sure practically possible: rte_lpm6_add_v1705 add_step if (depth <= bits_covered) { ... return 0 <--- so tbl_next stays untouched. tbl = tbl_next add_step tbl[tbl_index] So same comment as previous, if there is a practically available path, this patch makes it harder to find by hiding compiler warning, so adding maintainer for decision. > > Signed-off-by: Olivier Matz > --- > lib/librte_lpm/rte_lpm6.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/librte_lpm/rte_lpm6.c b/lib/librte_lpm/rte_lpm6.c > index b4a7df348..f9496fe1b 100644 > --- a/lib/librte_lpm/rte_lpm6.c > +++ b/lib/librte_lpm/rte_lpm6.c > @@ -518,7 +518,7 @@ rte_lpm6_add_v1705(struct rte_lpm6 *lpm, uint8_t *ip, uint8_t depth, > uint32_t next_hop) > { > struct rte_lpm6_tbl_entry *tbl; > - struct rte_lpm6_tbl_entry *tbl_next; > + struct rte_lpm6_tbl_entry *tbl_next = NULL; > int32_t rule_index; > int status; > uint8_t masked_ip[RTE_LPM6_IPV6_ADDR_SIZE]; >