From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E41F254878 for ; Sun, 6 Jul 2025 15:40:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751816435; cv=none; b=kKBLSt5WXdNd2wH0VxJWGnU2wWaQ2RxWjgJBglp6mOMEuEhjokpUDwOSqKpE3fkyq7nHSp88SI7tWItsM/9sQCAVbcqmq8Yp1GgqYBzEu849yqYcy27vJ3Y2iDl3sPtj3hMm+8viAnDNRQZG9cdRIbQHfZOU2ZiAIFcS7YS11Bo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751816435; c=relaxed/simple; bh=O/514BxAK/cylaA4ixlR2fqwEHzUpM2XqY37CsXHJtk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WFMZQtqiXhyZODo/R53R+9MwpCAba73m3T0/65W9Oxa7O8JD0Q5Dh731VFeoDcSy9tMj8W1XTfSv+De6cqDPIK00Aspr8Oa7DvVhzREioGlLAP+JQy6py4PhXatKnyJ+nYwq8sJS9sN/cpMldSBhAoyZik/heJVvubkhVmGNugA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=juDEntV1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="juDEntV1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F257C4CEED; Sun, 6 Jul 2025 15:40:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751816435; bh=O/514BxAK/cylaA4ixlR2fqwEHzUpM2XqY37CsXHJtk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=juDEntV1RkE8OLArbpQWOdgggPFuMXIOGFUHjzqrl/4QYVpMv7Q3VCDDDgeh+K2Yf 0+4iqlCneW6h1dQ+E8AC8dcJNS3vsvQFqOUfZ92t2O9JAK8CI/1qj/HLKhosBWcE3c fHgoihb8u8a3xePEnruZZCehyBLmx2UxBHaCFpFDC0y50EMy0ay0X6q2NULVKS+hWi I2gW2QuMGAf7b29j81JBV5R5zluH5Z3jDxgu4fcdckLEFRYi/rwmDA+RqcLeWLUkeJ InN2XUWrVxuKJd3Geff741Y3/CLB5km54iQmfZSaicGOVDVZYslP8Yc///En1TF1kw 9K8aWvuWFZ9UA== From: Gary Guo To: gnault@redhat.com Cc: davem@davemloft.net, idosch@idosch.org, kuba@kernel.org, ling@moedove.com, netdev@vger.kernel.org, noc@moedove.com, pabeni@redhat.com, Gary Guo Subject: Re: [BUG] net: gre: IPv6 link-local multicast is silently dropped (Regression) Date: Sun, 6 Jul 2025 16:40:30 +0100 Message-ID: <20250706154030.3010068-1-gary@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 2 Jul 2025 12:12:22 +0200, Guillaume Nault wrote: > Aiden, can you confirm that the following patch fixes the issue on your > side? Not Aiden, but I get hit with the same regression after updating kernel on my router from v6.12.28 to v6.12.35 today. Symptom for me is bird complaining about "Socket error: Network is unreachable", and strace shows that it's sending packets to ff02::1:6 and get hit with ENETUNREACH. I can confirm that applying this patch on top of v6.12.35 fixes the issue for me. I also took a look of the code, not a net expert, but this approach does look like a proper fix to me. Reviewed-by: Gary Guo Tested-by: Gary Guo > > ---- >8 ---- > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index ba2ec7c870cc..870a0bd6c2ba 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -3525,11 +3525,9 @@ static void addrconf_gre_config(struct net_device *dev) > > ASSERT_RTNL(); > > - idev = ipv6_find_idev(dev); > - if (IS_ERR(idev)) { > - pr_debug("%s: add_dev failed\n", __func__); > + idev = addrconf_add_dev(dev); > + if (IS_ERR(idev)) > return; > - } > > /* Generate the IPv6 link-local address using addrconf_addr_gen(), > * unless we have an IPv4 GRE device not bound to an IP address and > @@ -3543,9 +3541,6 @@ static void addrconf_gre_config(struct net_device *dev) > } > > add_v4_addrs(idev); > - > - if (dev->flags & IFF_POINTOPOINT) > - addrconf_add_mroute(dev); > } > #endif