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 136C22E738B; Mon, 17 Aug 2026 14:40:20 +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=1786977621; cv=none; b=nrw+9mDJh83dez7uoB7gT12ev8QoV4+TOKKuC5xMz3ICRxLE/ZK+DXcbi7WOxiQ94qdfiXidOhterVt9xyZrVSmbYsGwxitZ2zE7rhN4j1+lvsz47pONW1qdSD2QCmjyW7gyrrLsjaj1u25r21LTW+7ai6RdnOcKkSQ0mqzzOMg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977621; c=relaxed/simple; bh=MvlWUFI71uKYdR0GNlEEwjqbwcK2tEj0msj/izD0hto=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ha4mlr3G2/yxvZqOyJsBNqhvczbC3wvvwH9kpJdxPLasi5J4MBwDLeQtusY6p/Z39U0XEDKqjBSw5I3xfJuqbvOpA4ukjOdPG2u9V237Q/Z8/ltjJaxUseixoahW/L0EeDmKFOgSYMLH+JZ4YH7i2GX/pedxPDMEaSkGjEiQqNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FMFJjj18; 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="FMFJjj18" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C0B11F000E9; Mon, 17 Aug 2026 14:40:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977620; bh=fV2pBH6rDwXaAEYDoD9uLv0iJrc1HgsSw+YdZy11a7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FMFJjj18iqrQ5SYU90OBvu8rSMZAW6SUBdwtfnh+oftfEfk6ffN9g9dVo+98HOc3H cxC62ZZM4Q1FtWdrwjwr0olxYNO2s4nnQtMmJQpVFJWPronrI/3/Tgy+gG2BgBZlqL VjsFSHMaarRzqWgGwNbVOGYkFIPVqcvp/71HOnGY= 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 5.15 391/456] net: remove WARN_ON_ONCE() from sk_mc_loop() Date: Mon, 17 Aug 2026 15:33:01 +0200 Message-ID: <20260817132554.708619580@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@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 5.15-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 bf2bec10d5d6a..e5f8916aa85b8 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -724,7 +724,6 @@ 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