From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsMw9Wj1ybQh3zx5OROu+LcHmJ6reyaLgVrbOxvGHJRXeMJzKstvllt0JZFwzY+FTxYh+Qw ARC-Seal: i=1; a=rsa-sha256; t=1520451659; cv=none; d=google.com; s=arc-20160816; b=VBZlZ+Gmh0AOzqWY6ckAThdWHdGEMIh7KD2zgMn7D2snsZFcKNQA/PTV155IwDgbDc qdGKNRkWduZgsZYKelqpCWeQ3q1qU7w3UI+JVcf9zoi53wrG4jZ7XGfyS9hmq7TITavW E1LzPQiLayaDzoKOCT2Xmh0VUovBJsB81pGMQBXRvzSSEBQgXwhmdWyd/LyT9PiWdKpP oZjdI07cxRVE79kdxR/jn5vy37A4vatt3ymrXa0WKPdEFnfRLaRz+rob/LDqlKs/Wna5 tYRKo8kyXHNa2HEdVi9GHCQ9X44G1pZYjJvu2JesDWsukEC6153M0i5BgnLGw8776Y0V jDvQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=GUFrXlj4tFdc8cg9YSikBrZ9YRAfGJExrMOv/HHvFmA=; b=UAe24gJ+1NKQSGxcNwSoKK9uooVY1/+59U3ByCMxZD7sJ3RYVsY60PStTOYh+aB85K nbyXuO0pFG8J5yMmuX19hlFgCP3r7eiyVLhkynbfhzgPA033amNAXWN13Upo7ipp1Og2 9Tgbxqk4SWPeT2Wfa3mZArGn7TV4CFMptEVQPZgJKiYD/XBpy+HWAxIVPjGMcZkwVATc /B1YS+Y/iBd2Gggnx9CYxTbQSHVgSYO/OVTUKDx8iEzuXhTM6xqgLo4gEDSea0EGtT1V sbZZqOZPRXOyjYTdHL/3GawNbAnuOnHZXGxhKXilwGrarpsjGS9cNmM4PpvTbOoVvN2k ovdg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Sebor , Arnd Bergmann , "David S. Miller" Subject: [PATCH 4.15 042/122] ipv6 sit: work around bogus gcc-8 -Wrestrict warning Date: Wed, 7 Mar 2018 11:37:34 -0800 Message-Id: <20180307191735.112949252@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180307191729.190879024@linuxfoundation.org> References: <20180307191729.190879024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1594309119767792971?= X-GMAIL-MSGID: =?utf-8?q?1594309119767792971?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann [ Upstream commit ca79bec237f5809a7c3c59bd41cd0880aa889966 ] gcc-8 has a new warning that detects overlapping input and output arguments in memcpy(). It triggers for sit_init_net() calling ipip6_tunnel_clone_6rd(), which is actually correct: net/ipv6/sit.c: In function 'sit_init_net': net/ipv6/sit.c:192:3: error: 'memcpy' source argument is the same as destination [-Werror=restrict] The problem here is that the logic detecting the memcpy() arguments finds them to be the same, but the conditional that tests for the input and output of ipip6_tunnel_clone_6rd() to be identical is not a compile-time constant. We know that netdev_priv(t->dev) is the same as t for a tunnel device, and comparing "dev" directly here lets the compiler figure out as well that 'dev == sitn->fb_tunnel_dev' when called from sit_init_net(), so it no longer warns. This code is old, so Cc stable to make sure that we don't get the warning for older kernels built with new gcc. Cc: Martin Sebor Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83456 Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/sit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -182,7 +182,7 @@ static void ipip6_tunnel_clone_6rd(struc #ifdef CONFIG_IPV6_SIT_6RD struct ip_tunnel *t = netdev_priv(dev); - if (t->dev == sitn->fb_tunnel_dev) { + if (dev == sitn->fb_tunnel_dev) { ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0); t->ip6rd.relay_prefix = 0; t->ip6rd.prefixlen = 16;