From mboxrd@z Thu Jan 1 00:00:00 1970 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 57C4B42900D; Mon, 17 Aug 2026 14:46:07 +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=1786977968; cv=none; b=J5DddrTsx+/VMY8K3UVzsn/9S0bg3JRoUD94ToM6EIBAk/F+3AiPUKohHrMWpUarhImECby6u4A8pqBYdWSAwLdZ/GISHzrW4T1vjvrYGJ5F+R4WTjFcMZYHNNtO2EaAREYH7kIIkTFJu1NSw8lMaFlI7SErMn+mU1wsMF64nK8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977968; c=relaxed/simple; bh=3CMJRK1avPSF9Cb3tg6ULvm+jqKCJFp5gho4+PJyDtQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WaFpf27DiIC3bUfVvZAl3Slo9MmgM/xJbRS6Q9XfEFJfpKmw2O1cJZtcr1EI6WK3qyzu/2yFkBZhykZ/UWcytziv1s4EPi8RApnWlKxdAWiKTr2Vuq7iyPjB++ktnYuGukVF8+qJxvZa4xwKEoEeiNHkvyCvHchqdnErZs7IaR8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pn2aAW4Z; 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="pn2aAW4Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB49C1F000E9; Mon, 17 Aug 2026 14:46:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977967; bh=cvv8XJ8QIifBPcomsvazQRl3winqyefZHLvThTSFopg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pn2aAW4ZAR2catZqEDuVrOBNyTWSPzmBz4ZaZ02eeyhYguwp6U2Tk5FWRnn4XcRbT 1NUZIGYB5BaogBC6qnu98zWZ14UqczCY6JIMQWo71RT7CBCHep9pm6J2LyPYsfbt7v tuUQS9uwyAgAzRiNIS80aYtBrJRm2id23IfyDiu8= 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 6.12 055/181] net: remove WARN_ON_ONCE() from sk_mc_loop() Date: Mon, 17 Aug 2026 15:32:29 +0200 Message-ID: <20260817132537.582523595@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132535.394764707@linuxfoundation.org> References: <20260817132535.394764707@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 6.12-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 4a09e780406fe..e8b03cf3a428c 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -773,7 +773,6 @@ 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