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 D44A64B540C for ; Thu, 3 Sep 2026 14:24:35 +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=1788445486; cv=none; b=UZyD43+fi5i8pKhE2S6irTyT3HCheT0mDv9yG1Bo1OvSxDOnSpY4N+6DYgzBhCU0Qbf+eDJjk8aBoLsOZu+wDCNyg1HhxrX9XEccvIEuIHSZXuJGcNVJP43dIIEafYhtIwchF/F52/pdbrMNmbFr3iuah/yugOLizVqRnRv4zkk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788445486; c=relaxed/simple; bh=BZX455KNauI/ng0h8eI+d6Idq6973+Iri8rtHOm0ckg=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=j4uhvuo2G+a2TwQTr0zRc9RBx1I3v0oAfq2HLkuVy7FCek17Dxt7U+DvjeQt52aAcfc58CkOg3jZuSN7EPARxHbrUTzfVuvGm9+V6ATRTxYWiAdNYhIfW52pknLwCLKIqeecGxgJRrTugidko37eq+npS6WqtwHsBFDpq8kORvI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AtafgmMd; 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="AtafgmMd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 423681F00A3D; Thu, 3 Sep 2026 14:24:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788445475; bh=Iwr1O2oLSLqfMHxR0EMYDCw2k55yQ47GdquhRpaZVtU=; h=Subject:To:Cc:From:Date; b=AtafgmMd/2cYix1MRM83WiaWGJwkCTBkUEOaFBUDxssoFiHr7mAcPQtq5yKTsylF9 OMb8PrdGFPTWybeB4MTSrUhWx5NgUdotnVuA2dfxa+YI1In3k7+Za/OQXlSV+cW+Ld XIFaGqHMD4bPtvHad3r1EcTshOw8rk6hd6R4cexQ= Subject: FAILED: patch "[PATCH] ip: orphan prefetched skbs before multicast forwarding" failed to apply to 5.15-stable tree To: zhilinz@nebusec.ai,idosch@nvidia.com,pabeni@redhat.com,vega@nebusec.ai Cc: From: Date: Thu, 03 Sep 2026 16:00:19 +0200 Message-ID: <2026090319-antiques-palm-c286@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e36ce6e78fe3fc3c071a26750783b7ba081ce10d # git commit -s git send-email --to '' --in-reply-to '2026090319-antiques-palm-c286@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e36ce6e78fe3fc3c071a26750783b7ba081ce10d Mon Sep 17 00:00:00 2001 From: Zhiling Zou Date: Thu, 13 Aug 2026 00:36:38 +0800 Subject: [PATCH] ip: orphan prefetched skbs before multicast forwarding IPv4 and IPv6 input preserve an skb->sk association installed by bpf_sk_assign() so that local delivery can use the selected socket under RCU. Both address families can also prefetch a socket in UDP early demux. In both paths (BPF and UDP early demux) a reference is not guaranteed to be held on the socket. When a multicast packet is not locally deliverable, IPv6 hands the original skb to ip6_mr_input(). IPv4's ip_mr_input() similarly keeps the original skb when local delivery is not needed. Either path can put the skb on an unresolved multicast route queue or forward it after the receive-side RCU section ends. After the prefetched socket is destroyed, a later skb free invokes sock_pfree() and dereferences the stale skb->sk. Orphan the skb before each non-local multicast forwarding path. Local delivery retains the original skb; the existing skb_clone() calls provide multicast forwarding with a socket-free clone. Fixes: cf7fbe660f2d ("bpf: Add socket assign support") Fixes: 08842c43d016 ("udp: no longer touch sk->sk_refcnt in early demux") Cc: stable@vger.kernel.org Reported-by: Vega Signed-off-by: Zhiling Zou Reported-by: Vega Signed-off-by: Zhiling Zou Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/0c52eb3d7532aaf8bccf37e0f7c922143c639735.1786552223.git.zhilinz@nebusec.ai Signed-off-by: Paolo Abeni diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 1d9a4ac14fce..e5f2b1c6150d 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -2213,6 +2213,9 @@ int ip_mr_input(struct sk_buff *skb) if (IPCB(skb)->flags & IPSKB_FORWARDED) goto dont_forward; + if (!local) + skb_orphan(skb); + mrt = ipmr_rt_fib_lookup(net, skb); if (IS_ERR(mrt)) { kfree_skb(skb); diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c index 8972863c93ee..d332ec60f915 100644 --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -622,6 +622,7 @@ int ip6_mc_input(struct sk_buff *skb) if (deliver) { skb2 = skb_clone(skb, GFP_ATOMIC); } else { + skb_orphan(skb); skb2 = skb; skb = NULL; }