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 785F14ABBAD; Thu, 17 Sep 2026 15:35:27 +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=1789659334; cv=none; b=l0JpNfC0WGDA+5elTiPzG3tAHKRA4gRpB9oje9iy6fO0VI2Um+SsgC9Z2+1Ibc0mYo16ZaQUZZwaEdE46VxyQiqUSygaXOjE1y8vfgtmzocmY6V9L9mxmo1ab3sgvlJBT+fyWukDe0ApjiCsSld43yzA8YkrDl9jourOlDyY6G0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659334; c=relaxed/simple; bh=yr2JSTahjmxav2VyZfO4sr/8ER/rAIWaXkWMhmsr8f8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R97caoPYByuTg9H0Qg45xYGuRMv70/rIIawH12lEy7x5vsuvY/9PDumr/OEWCfSwBkRl50t+EPqjrkap2hqBBw6K3O2+HNQa/20QpK1n/Nt6tHt9TlJV04Cnfj6A2MEmig7M3sAUd+/wO/+XoTHjflMRNrWjYM9csD5WqFh0Ync= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=trmmAp2x; 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="trmmAp2x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 524AE1F000FF; Thu, 17 Sep 2026 15:35:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789659323; bh=+lH2Vq++U3fmtyeen1iFLohXWOhR4ZBuyOXV+JTx9fs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=trmmAp2xTjWG49Wj0Vsc+vXB+zJ75XSPqa6wul6geZtv1xN3I9q8+yEJx8WIekGWv cfAvYpNOLZ2LU+dzaUISHXdCVXGtA3CbCypGVPD6yFpfPiIOWByWvhey4xUmfj+9mS KR6IyC3g0m2x/U1nNpymFL7PV3QW2x2f3yvBMxXg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhaoping Shu , HW He , Willem de Bruijn , Paolo Abeni , Sasha Levin Subject: [PATCH 7.2 219/733] net: gro: Fix nesting of TCP GSO SKBs in skb_gro_receive_list() Date: Thu, 17 Sep 2026 16:08:47 +0100 Message-ID: <20260917151356.660090351@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: HW He [ Upstream commit 66817a9794263cd2a5dc4e99bf8e5fcc5ff7181e ] Fraglist GRO and hardware GRO can create an fraglist of HW-GRO packets. This cannot be segmented back into the original form on TCP tethering scenario. Avoid constructing such a GSO packet, by flushing an already built fraglist GRO packet if a hardware GRO packet arrives. Scenario (Tethering/Forwarding): 1.Driver submits a single TCP packet, P1. P1 is kept in the gro_list as the first packet. 2. The driver submits a TCP GSO skb, P2. P2 has already aggregated multiple TCP packets by HW_GRO, and its non-linear data is stored in frags[]. 3. P1 and P2 match the GRO rules, and since there is no local socket, they are aggregated by skb_gro_receive_list(). The resulting skb, P3, has a frag_list entry that still contains frags[]: P3: [ Linear Data ] -> frag_list -> [ Linear Data ] [ frag[1] ] [ frag[2] ] ... 4. Later, tcp4_gso_segment() or tcp6_gso_segment() calls skb_segment_list() to segment P3. However, skb_segment_list() only segments the entries in frag_list. It does not segment the frags[] inside P2, so P3 is not restored to the original packets, which leads to IP fragmentation or packet drop in the following path. Check skb_is_gso(skb) and current GRO method, make sure fraglist GRO applies to consecutive non-GSO skb, others adopt regular GRO path. Fixes: 8d95dc474f85 ("net: add code for TCP fraglist GRO") Signed-off-by: Zhaoping Shu Signed-off-by: HW He Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260901082312.14596-1-zhaoping.shu@mediatek.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/ipv4/tcp_offload.c | 22 ++++++++++++++++------ net/ipv6/tcpv6_offload.c | 15 +++++++++++++-- 2 files changed, 29 insertions(+), 8 deletions(-) diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index 3b1fdcd3cb29b..e74d99ca9face 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -332,6 +332,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb, flush |= skb->ip_summed != p->ip_summed; flush |= skb->csum_level != p->csum_level; flush |= NAPI_GRO_CB(p)->count >= 64; + flush |= NAPI_GRO_CB(p)->is_flist != NAPI_GRO_CB(skb)->is_flist; skb_set_network_header(skb, skb_gro_receive_network_offset(skb)); if (flush || skb_gro_receive_list(p, skb)) @@ -395,12 +396,20 @@ static void tcp4_check_fraglist_gro(struct list_head *head, struct sk_buff *skb, struct net *net; int iif, sdif; - if (likely(!(skb->dev->features & NETIF_F_GRO_FRAGLIST))) - return; - p = tcp_gro_lookup(head, th); if (p) { - NAPI_GRO_CB(skb)->is_flist = NAPI_GRO_CB(p)->is_flist; + /* flist GRO applies to consecutive non-GSO skbs */ + if (!skb_is_gso(skb) || !NAPI_GRO_CB(p)->is_flist) { + NAPI_GRO_CB(skb)->is_flist = NAPI_GRO_CB(p)->is_flist; + return; + } + + /* Fall back to the regular GRO path */ + if (NAPI_GRO_CB(p)->count == 1) + NAPI_GRO_CB(p)->is_flist = 0; + + NAPI_GRO_CB(skb)->is_flist = 0; + return; } @@ -410,7 +419,7 @@ static void tcp4_check_fraglist_gro(struct list_head *head, struct sk_buff *skb, sk = __inet_lookup_established(net, iph->saddr, th->source, iph->daddr, ntohs(th->dest), iif, sdif); - NAPI_GRO_CB(skb)->is_flist = !sk; + NAPI_GRO_CB(skb)->is_flist = !sk && !skb_is_gso(skb); if (sk) sock_gen_put(sk); } @@ -430,7 +439,8 @@ struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb) if (!th) goto flush; - tcp4_check_fraglist_gro(head, skb, th); + if (unlikely(skb->dev->features & NETIF_F_GRO_FRAGLIST)) + tcp4_check_fraglist_gro(head, skb, th); return tcp_gro_receive(head, skb, th); diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c index f2a659cd6183c..eec3778855eb8 100644 --- a/net/ipv6/tcpv6_offload.c +++ b/net/ipv6/tcpv6_offload.c @@ -26,7 +26,18 @@ static void tcp6_check_fraglist_gro(struct list_head *head, struct sk_buff *skb, p = tcp_gro_lookup(head, th); if (p) { - NAPI_GRO_CB(skb)->is_flist = NAPI_GRO_CB(p)->is_flist; + /* flist GRO applies to consecutive non-GSO skbs */ + if (!skb_is_gso(skb) || !NAPI_GRO_CB(p)->is_flist) { + NAPI_GRO_CB(skb)->is_flist = NAPI_GRO_CB(p)->is_flist; + return; + } + + /* Fall back to the regular GRO path */ + if (NAPI_GRO_CB(p)->count == 1) + NAPI_GRO_CB(p)->is_flist = 0; + + NAPI_GRO_CB(skb)->is_flist = 0; + return; } @@ -36,7 +47,7 @@ static void tcp6_check_fraglist_gro(struct list_head *head, struct sk_buff *skb, sk = __inet6_lookup_established(net, &hdr->saddr, th->source, &hdr->daddr, ntohs(th->dest), iif, sdif); - NAPI_GRO_CB(skb)->is_flist = !sk; + NAPI_GRO_CB(skb)->is_flist = !sk && !skb_is_gso(skb); if (sk) sock_gen_put(sk); #endif /* IS_ENABLED(CONFIG_IPV6) */ -- 2.53.0