* [PATCH 6.1.y 3/3] net: fix segmentation of forwarding fraglist GRO
@ 2026-03-02 6:54 Li hongliang
2026-03-23 13:03 ` Patch "net: fix segmentation of forwarding fraglist GRO" has been added to the 6.1-stable tree gregkh
0 siblings, 1 reply; 2+ messages in thread
From: Li hongliang @ 2026-03-02 6:54 UTC (permalink / raw)
To: gregkh, stable, jibin.zhang
Cc: patches, linux-kernel, ast, daniel, andrii, martin.lau, song, yhs,
john.fastabend, kpsingh, sdf, haoluo, jolsa, davem, edumazet,
kuba, pabeni, yoshfuji, dsahern, matthias.bgg, willemb,
steffen.klassert, bpf, netdev, linux-arm-kernel, linux-mediatek
From: Jibin Zhang <jibin.zhang@mediatek.com>
[ Upstream commit 426ca15c7f6cb6562a081341ca88893a50c59fa2 ]
This patch enhances GSO segment handling by properly checking
the SKB_GSO_DODGY flag for frag_list GSO packets, addressing
low throughput issues observed when a station accesses IPv4
servers via hotspots with an IPv6-only upstream interface.
Specifically, it fixes a bug in GSO segmentation when forwarding
GRO packets containing a frag_list. The function skb_segment_list
cannot correctly process GRO skbs that have been converted by XLAT,
since XLAT only translates the header of the head skb. Consequently,
skbs in the frag_list may remain untranslated, resulting in protocol
inconsistencies and reduced throughput.
To address this, the patch explicitly sets the SKB_GSO_DODGY flag
for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers
(bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO
packets as potentially modified after protocol translation. As a
result, GSO segmentation will avoid using skb_segment_list and
instead falls back to skb_segment for packets with the SKB_GSO_DODGY
flag. This ensures that only safe and fully translated frag_list
packets are processed by skb_segment_list, resolving protocol
inconsistencies and improving throughput when forwarding GRO packets
converted by XLAT.
Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260126152114.1211-1-jibin.zhang@mediatek.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Li hongliang <1468888505@139.com>
---
net/core/filter.c | 2 ++
net/ipv4/tcp_offload.c | 3 ++-
net/ipv4/udp_offload.c | 3 ++-
net/ipv6/tcpv6_offload.c | 3 ++-
4 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index e19bf63ad9a4..d8facc927337 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3326,6 +3326,7 @@ static int bpf_skb_proto_4_to_6(struct sk_buff *skb)
shinfo->gso_type &= ~SKB_GSO_TCPV4;
shinfo->gso_type |= SKB_GSO_TCPV6;
}
+ shinfo->gso_type |= SKB_GSO_DODGY;
}
skb->protocol = htons(ETH_P_IPV6);
@@ -3356,6 +3357,7 @@ static int bpf_skb_proto_6_to_4(struct sk_buff *skb)
shinfo->gso_type &= ~SKB_GSO_TCPV6;
shinfo->gso_type |= SKB_GSO_TCPV4;
}
+ shinfo->gso_type |= SKB_GSO_DODGY;
}
skb->protocol = htons(ETH_P_IP);
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 9fbb70312159..b0e62c081998 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -106,7 +106,8 @@ static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) {
struct tcphdr *th = tcp_hdr(skb);
- if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size)
+ if ((skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size) &&
+ !(skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
return __tcp4_gso_segment_list(skb, features);
skb->ip_summed = CHECKSUM_NONE;
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 593108049ab7..58cabb2bb32a 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -351,7 +351,8 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
/* Detect modified geometry and pass those to skb_segment. */
- if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
+ if ((skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size) &&
+ !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_DODGY))
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
ret = __skb_linearize(gso_skb);
diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
index 81959fd6fe36..976608aa049b 100644
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -108,7 +108,8 @@ static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) {
struct tcphdr *th = tcp_hdr(skb);
- if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size)
+ if ((skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size) &&
+ !(skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
return __tcp6_gso_segment_list(skb, features);
skb->ip_summed = CHECKSUM_NONE;
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Patch "net: fix segmentation of forwarding fraglist GRO" has been added to the 6.1-stable tree
2026-03-02 6:54 [PATCH 6.1.y 3/3] net: fix segmentation of forwarding fraglist GRO Li hongliang
@ 2026-03-23 13:03 ` gregkh
0 siblings, 0 replies; 2+ messages in thread
From: gregkh @ 2026-03-23 13:03 UTC (permalink / raw)
To: 1468888505, andrii, ast, daniel, davem, dsahern, edumazet, gregkh,
haoluo, jibin.zhang, john.fastabend, jolsa, kpsingh, kuba,
linux-arm-kernel, linux-mediatek, martin.lau, matthias.bgg,
pabeni, patches, sdf, song, steffen.klassert, willemb, yhs,
yoshfuji
Cc: stable-commits
This is a note to let you know that I've just added the patch titled
net: fix segmentation of forwarding fraglist GRO
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fix-segmentation-of-forwarding-fraglist-gro.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
From 1468888505@139.com Mon Mar 2 07:54:33 2026
From: Li hongliang <1468888505@139.com>
Date: Mon, 2 Mar 2026 14:54:27 +0800
Subject: net: fix segmentation of forwarding fraglist GRO
To: gregkh@linuxfoundation.org, stable@vger.kernel.org, jibin.zhang@mediatek.com
Cc: patches@lists.linux.dev, linux-kernel@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, yoshfuji@linux-ipv6.org, dsahern@kernel.org, matthias.bgg@gmail.com, willemb@google.com, steffen.klassert@secunet.com, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org
Message-ID: <20260302065427.2695392-1-1468888505@139.com>
From: Jibin Zhang <jibin.zhang@mediatek.com>
[ Upstream commit 426ca15c7f6cb6562a081341ca88893a50c59fa2 ]
This patch enhances GSO segment handling by properly checking
the SKB_GSO_DODGY flag for frag_list GSO packets, addressing
low throughput issues observed when a station accesses IPv4
servers via hotspots with an IPv6-only upstream interface.
Specifically, it fixes a bug in GSO segmentation when forwarding
GRO packets containing a frag_list. The function skb_segment_list
cannot correctly process GRO skbs that have been converted by XLAT,
since XLAT only translates the header of the head skb. Consequently,
skbs in the frag_list may remain untranslated, resulting in protocol
inconsistencies and reduced throughput.
To address this, the patch explicitly sets the SKB_GSO_DODGY flag
for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers
(bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO
packets as potentially modified after protocol translation. As a
result, GSO segmentation will avoid using skb_segment_list and
instead falls back to skb_segment for packets with the SKB_GSO_DODGY
flag. This ensures that only safe and fully translated frag_list
packets are processed by skb_segment_list, resolving protocol
inconsistencies and improving throughput when forwarding GRO packets
converted by XLAT.
Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260126152114.1211-1-jibin.zhang@mediatek.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Li hongliang <1468888505@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/filter.c | 2 ++
net/ipv4/tcp_offload.c | 3 ++-
net/ipv4/udp_offload.c | 3 ++-
net/ipv6/tcpv6_offload.c | 3 ++-
4 files changed, 8 insertions(+), 3 deletions(-)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3333,6 +3333,7 @@ static int bpf_skb_proto_4_to_6(struct s
shinfo->gso_type &= ~SKB_GSO_TCPV4;
shinfo->gso_type |= SKB_GSO_TCPV6;
}
+ shinfo->gso_type |= SKB_GSO_DODGY;
}
bpf_skb_change_protocol(skb, ETH_P_IPV6);
@@ -3363,6 +3364,7 @@ static int bpf_skb_proto_6_to_4(struct s
shinfo->gso_type &= ~SKB_GSO_TCPV6;
shinfo->gso_type |= SKB_GSO_TCPV4;
}
+ shinfo->gso_type |= SKB_GSO_DODGY;
}
bpf_skb_change_protocol(skb, ETH_P_IP);
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -106,7 +106,8 @@ static struct sk_buff *tcp4_gso_segment(
if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) {
struct tcphdr *th = tcp_hdr(skb);
- if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size)
+ if ((skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size) &&
+ !(skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
return __tcp4_gso_segment_list(skb, features);
skb->ip_summed = CHECKSUM_NONE;
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -351,7 +351,8 @@ struct sk_buff *__udp_gso_segment(struct
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
/* Detect modified geometry and pass those to skb_segment. */
- if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
+ if ((skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size) &&
+ !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_DODGY))
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
ret = __skb_linearize(gso_skb);
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -108,7 +108,8 @@ static struct sk_buff *tcp6_gso_segment(
if (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) {
struct tcphdr *th = tcp_hdr(skb);
- if (skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size)
+ if ((skb_pagelen(skb) - th->doff * 4 == skb_shinfo(skb)->gso_size) &&
+ !(skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
return __tcp6_gso_segment_list(skb, features);
skb->ip_summed = CHECKSUM_NONE;
Patches currently in stable-queue which might be from 1468888505@139.com are
queue-6.1/net-fix-segmentation-of-forwarding-fraglist-gro.patch
queue-6.1/net-gso-fix-tcp-fraglist-segmentation-after-pull-from-frag_list.patch
queue-6.1/net-add-support-for-segmenting-tcp-fraglist-gso-packets.patch
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2026-03-23 13:03 ` Patch "net: fix segmentation of forwarding fraglist GRO" has been added to the 6.1-stable tree gregkh
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