Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4D11B3EB7F8; Mon, 17 Aug 2026 13:55:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786974911; cv=none; b=U4AtclhGVHlceKqynr4HdiJP6m763i7tKWFhDVujDuqHPpNqVE9MD5OTaZ/SOo3xJTjY0K++T0R1WKowr5hvKKg/icsW2PKqaJsnZcjP8ik4IWgZYojuczZtyYfarnZsh0JdT5pGj/NMio5fIvxSk8JNoK/RCYeMxq2anynqkck= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786974911; c=relaxed/simple; bh=+6eyQ0j/bU6xcFiAT82XtIWzsxp2FClBzK/yZ4UCVEo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CwMIVZDRpclsjuE3miCCteJHrJ/CATaEB9PAcHAVdg+hA6NSTse4OcvZAQN1IhI0Nqb0MmaucibWCVjk0jS3uOE9y/QavUrVnNtumexOXZQoDEdDZF6E2vDemNNJtu8jrIpLv/zjcaDuq/P9zE7wDLS9D3oTJq5ckeKqebj0B3M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mA/HVp2b; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mA/HVp2b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 237871F000E9; Mon, 17 Aug 2026 13:55:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786974906; bh=xxabxowkHx3L/qNp3wW3+KDe45k9RErhxNZfWI2LUic=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mA/HVp2brLwWeq/vUelDKMMYBSTNCuzEBoO1SUddk9ydDUk78LcqKpfk6A8gBnppw EEPAkilnId3Pv1T9XK3nAurSdfl5SHYge1WuMFq3CHgr13WXMTPAxRcMeX5ozPhL27 G0MVHJnGIa1HE62O7mpUvAMcFk6MqCZq/lwn3dao= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+22c3218a6fa219e47321@syzkaller.appspotmail.com, Eric Dumazet , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 095/250] net: remove WARN_ON_ONCE() from sk_mc_loop() Date: Mon, 17 Aug 2026 15:30:56 +0200 Message-ID: <20260817132540.390864300@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132536.466235697@linuxfoundation.org> References: <20260817132536.466235697@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit b8a39a09ae4eaae04309e1e38ed6a1101d967496 ] sk_mc_loop() can be called for sockets that are neither AF_INET nor AF_INET6 (e.g. AF_PACKET sockets when sending packets via raw/packet socket over virtual devices such as VRF or ipvlan). In such cases, sk_family is not AF_INET/AF_INET6 and sk_mc_loop() falls through the switch statement and triggers WARN_ON_ONCE(1). Non-INET sockets do not support IP_MULTICAST_LOOP or IPV6_MULTICAST_LOOP options, so loopback should default to true without generating a warning. Fixes: f60e5990d9c1 ("ipv6: protect skb->sk accesses from recursive dereference inside the stack") Reported-by: syzbot+22c3218a6fa219e47321@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6a72024c.13623e66.bdc14.0019.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260804152048.2134341-1-edumazet@google.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/core/sock.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/core/sock.c b/net/core/sock.c index 5a658606c50e8..b69c574c20ad3 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -786,7 +786,6 @@ bool sk_mc_loop(const struct sock *sk) return inet6_test_bit(MC6_LOOP, sk); #endif } - WARN_ON_ONCE(1); return true; } EXPORT_SYMBOL(sk_mc_loop); -- 2.53.0