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 D23C34399F8; Mon, 17 Aug 2026 14:54:33 +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=1786978475; cv=none; b=k3o/DYMBL4brbZMHKRB7FAxx/W9xnzer86cK419UPeDronX8Pzc2tNHhdouU4pzlROlA62qVhiOKL534bvDCN9V6ZNzKdVjPRBym03W6Ad0vMsBRMf4qjE01k/uS3lPiqHkapcovSowQ8n50+fG8zPX4IUwSy+qUNiUiwGqdYKU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786978475; c=relaxed/simple; bh=ohE5EPTUERhn3NGJHwRlmnJGWsemlIzbuEL/mMd6JJE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A8tt7fj+2EdwNsRiOjDBEFVC/vITh2gt/7VDkqPCAbIhkEbxRnep64KV0srrRlb8YyL7yq3JEI1iZLKCwsHMnSJW8IsETXGUNnjQKyY1NoYXAcXI5/CIJvv1sBtmDle9Oy6Ahon8uYRr7zSyiEE64/vsgF4b3a8S0a1I6Vl3Nik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IrMoTeol; 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="IrMoTeol" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 080721F000E9; Mon, 17 Aug 2026 14:54:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786978473; bh=czMy6j+olyWiJ14kT2Ja37CiFr9lPm7/6+IAvRWpbsk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IrMoTeol/8BiNDt2D2YyJ4NEgQKuoXp71nWWgpjAmtdt/c1zdWcaClVvImAGD0D3v U5cAMSrWYoJsSps/PFBMfyxt+/DD+qTrZ1mmuoS9clfjhAJLgaPSUScmksUt6yj4yO leIOjFR5r4eiS05d0icaW4rRZrZM8+cBz4StYilI= 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 6.6 050/156] net: remove WARN_ON_ONCE() from sk_mc_loop() Date: Mon, 17 Aug 2026 15:33:04 +0200 Message-ID: <20260817132536.551178595@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132534.666299318@linuxfoundation.org> References: <20260817132534.666299318@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 6.6-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 87e6060c8bca7..846e95805c199 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -776,7 +776,6 @@ bool sk_mc_loop(struct sock *sk) return inet6_sk(sk)->mc_loop; #endif } - WARN_ON_ONCE(1); return true; } EXPORT_SYMBOL(sk_mc_loop); -- 2.53.0