Re: [REGRESSION] aquantia: Sunshine/Moonlight UDP video streaming broken since 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL")

Re: [REGRESSION] aquantia: Sunshine/Moonlight UDP video streaming broken since 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL")

[Gal Pressman]

On 27/04/2026 21:26, Matthew Schwartz wrote:
> On 4/27/26 11:09 AM, Gal Pressman wrote:
>> Hello Matthew,
>>
>> On 27/04/2026 2:20, Matthew Schwartz wrote:
>>> Hello,
>>>
>>> When using a previously working setup of remote streaming from my workstation to another device via Sunshine (the host server) and Moonlight (the client app) on my home network, I no longer receive any video output on the client app after upgrading my host workstation to kernel 7.0. Reverting back to kernel 6.19 on the host restored my setup to a working state.
>>>
>>> After bisecting, I landed on 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL") as the first bad commit. I confirmed this by moving the cable to my second on-board NIC (Intel) on the same workstation, which restored video output without any other kernel changes. My affected on-board NIC is Aquantia AQC113 [1d6a:04c0] (rev 03), atlantic driver, firmware 1.3.34, MTU 1500.
>>>
>>> Looking into it a bit further, ethtool -K enp97s0 tx-udp-segmentation off also serves as a workaround on my Aquantia port without changing to my other ethernet port. The working Intel NIC reports tx-udp-segmentation as "off [fixed]", so traffic falls back to software UDP segmentation on there.
>>>
>>> Please let me know if there's any additional info I can provide.
>>>
>>> Thanks,
>>> Matt
>>>
>>> #regzbot introduced: 5b4015ad833c
>>
>> Thank you for the report and the bisect!
>>
>> I will take a look and try to figure out what's wrong (though I don't
>> have real hardware to test on).
>> Is the userspace app open source? can I see its code and try to run it
>> myself?
> 
> Thanks for the reply. The code for Sunshine is available here: https://github.com/LizardByte/Sunshine and the code for Moonlight is here: https://github.com/moonlight-stream/moonlight-qt.
> 
> I have been using the Arch Linux Sunshine package which I installed by following the Linux instructions here: https://docs.lizardbyte.dev/projects/sunshine/latest/md_docs_2getting__started.html, but there are also binaries for other distros or it's buildable from source. For Moonlight, I have been using the Flatpak distributed on Flathub because the client device runs an atomic rootfs, but you can also use any other device that Moonlight supports.
> 
>>
>> I will be OOO for the rest of the week, hope to have some meaningful
>> reply by the end of next week.
> 

I think I see the issue, do you mind testing the following diff?

index a0813d425b71..5bd1706b11b0 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -599,10 +599,22 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 		uh = udp_hdr(seg);
 	}

-	/* last packet can be partial gso_size, account for that in checksum */
-	newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
-		       seg->data_len);
-	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
+	if (skb_is_gso(seg)) {
+		newlen = msslen;
+	} else {
+		/* last packet can be partial gso_size, account for that in
+		 * checksum.
+		 */
+		newlen = htons(skb_tail_pointer(seg) -
+			       skb_transport_header(seg) + seg->data_len);
+		check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
+	}

 	uh->len = newlen;
 	uh->check = check;

Re: [REGRESSION] aquantia: Sunshine/Moonlight UDP video streaming broken since 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL")

[Matthew Schwartz]

> On May 5, 2026, at 8:05 AM, Gal Pressman <gal@nvidia.com> wrote:
> 
> On 27/04/2026 21:26, Matthew Schwartz wrote:
>>> On 4/27/26 11:09 AM, Gal Pressman wrote:
>>> Hello Matthew,
>>> 
>>> On 27/04/2026 2:20, Matthew Schwartz wrote:
>>>> Hello,
>>>> 
>>>> When using a previously working setup of remote streaming from my workstation to another device via Sunshine (the host server) and Moonlight (the client app) on my home network, I no longer receive any video output on the client app after upgrading my host workstation to kernel 7.0. Reverting back to kernel 6.19 on the host restored my setup to a working state.
>>>> 
>>>> After bisecting, I landed on 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL") as the first bad commit. I confirmed this by moving the cable to my second on-board NIC (Intel) on the same workstation, which restored video output without any other kernel changes. My affected on-board NIC is Aquantia AQC113 [1d6a:04c0] (rev 03), atlantic driver, firmware 1.3.34, MTU 1500.
>>>> 
>>>> Looking into it a bit further, ethtool -K enp97s0 tx-udp-segmentation off also serves as a workaround on my Aquantia port without changing to my other ethernet port. The working Intel NIC reports tx-udp-segmentation as "off [fixed]", so traffic falls back to software UDP segmentation on there.
>>>> 
>>>> Please let me know if there's any additional info I can provide.
>>>> 
>>>> Thanks,
>>>> Matt
>>>> 
>>>> #regzbot introduced: 5b4015ad833c
>>> 
>>> Thank you for the report and the bisect!
>>> 
>>> I will take a look and try to figure out what's wrong (though I don't
>>> have real hardware to test on).
>>> Is the userspace app open source? can I see its code and try to run it
>>> myself?
>> 
>> Thanks for the reply. The code for Sunshine is available here: https://github.com/LizardByte/Sunshine and the code for Moonlight is here: https://github.com/moonlight-stream/moonlight-qt.
>> 
>> I have been using the Arch Linux Sunshine package which I installed by following the Linux instructions here: https://docs.lizardbyte.dev/projects/sunshine/latest/md_docs_2getting__started.html, but there are also binaries for other distros or it's buildable from source. For Moonlight, I have been using the Flatpak distributed on Flathub because the client device runs an atomic rootfs, but you can also use any other device that Moonlight supports.
>> 
>>> 
>>> I will be OOO for the rest of the week, hope to have some meaningful
>>> reply by the end of next week.
>> 
> 
> I think I see the issue, do you mind testing the following diff?

Sorry for the delay. I applied this diff and I’m able to stream from my host to clients again without any issues.

If you send this version upstream, feel free to add my Tested-by to it.

Thanks,
Matt

> 
> index a0813d425b71..5bd1706b11b0 100644
> --- a/net/ipv4/udp_offload.c
> +++ b/net/ipv4/udp_offload.c
> @@ -599,10 +599,22 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
>        uh = udp_hdr(seg);
>    }
> 
> -    /* last packet can be partial gso_size, account for that in checksum */
> -    newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
> -               seg->data_len);
> -    check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
> +    if (skb_is_gso(seg)) {
> +        newlen = msslen;
> +    } else {
> +        /* last packet can be partial gso_size, account for that in
> +         * checksum.
> +         */
> +        newlen = htons(skb_tail_pointer(seg) -
> +                   skb_transport_header(seg) + seg->data_len);
> +        check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
> +    }
> 
>    uh->len = newlen;
>    uh->check = check;

Re: [REGRESSION] aquantia: Sunshine/Moonlight UDP video streaming broken since 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL")

[Gal Pressman]

On 06/05/2026 10:49, Matthew Schwartz wrote:
> 
> 
>> On May 5, 2026, at 8:05 AM, Gal Pressman <gal@nvidia.com> wrote:
>>
>> On 27/04/2026 21:26, Matthew Schwartz wrote:
>>>> On 4/27/26 11:09 AM, Gal Pressman wrote:
>>>> Hello Matthew,
>>>>
>>>> On 27/04/2026 2:20, Matthew Schwartz wrote:
>>>>> Hello,
>>>>>
>>>>> When using a previously working setup of remote streaming from my workstation to another device via Sunshine (the host server) and Moonlight (the client app) on my home network, I no longer receive any video output on the client app after upgrading my host workstation to kernel 7.0. Reverting back to kernel 6.19 on the host restored my setup to a working state.
>>>>>
>>>>> After bisecting, I landed on 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL") as the first bad commit. I confirmed this by moving the cable to my second on-board NIC (Intel) on the same workstation, which restored video output without any other kernel changes. My affected on-board NIC is Aquantia AQC113 [1d6a:04c0] (rev 03), atlantic driver, firmware 1.3.34, MTU 1500.
>>>>>
>>>>> Looking into it a bit further, ethtool -K enp97s0 tx-udp-segmentation off also serves as a workaround on my Aquantia port without changing to my other ethernet port. The working Intel NIC reports tx-udp-segmentation as "off [fixed]", so traffic falls back to software UDP segmentation on there.
>>>>>
>>>>> Please let me know if there's any additional info I can provide.
>>>>>
>>>>> Thanks,
>>>>> Matt
>>>>>
>>>>> #regzbot introduced: 5b4015ad833c
>>>>
>>>> Thank you for the report and the bisect!
>>>>
>>>> I will take a look and try to figure out what's wrong (though I don't
>>>> have real hardware to test on).
>>>> Is the userspace app open source? can I see its code and try to run it
>>>> myself?
>>>
>>> Thanks for the reply. The code for Sunshine is available here: https://github.com/LizardByte/Sunshine and the code for Moonlight is here: https://github.com/moonlight-stream/moonlight-qt.
>>>
>>> I have been using the Arch Linux Sunshine package which I installed by following the Linux instructions here: https://docs.lizardbyte.dev/projects/sunshine/latest/md_docs_2getting__started.html, but there are also binaries for other distros or it's buildable from source. For Moonlight, I have been using the Flatpak distributed on Flathub because the client device runs an atomic rootfs, but you can also use any other device that Moonlight supports.
>>>
>>>>
>>>> I will be OOO for the rest of the week, hope to have some meaningful
>>>> reply by the end of next week.
>>>
>>
>> I think I see the issue, do you mind testing the following diff?
> 
> Sorry for the delay. I applied this diff and I’m able to stream from my host to clients again without any issues.
> 
> If you send this version upstream, feel free to add my Tested-by to it.

Thanks for verifying!

I will finalize this and submit a proper patch soon.

Re: [REGRESSION] aquantia: Sunshine/Moonlight UDP video streaming broken since 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL")

[Gal Pressman]

On 06/05/2026 17:20, Gal Pressman wrote:
> On 06/05/2026 10:49, Matthew Schwartz wrote:
>>
>>
>>> On May 5, 2026, at 8:05 AM, Gal Pressman <gal@nvidia.com> wrote:
>>>
>>> On 27/04/2026 21:26, Matthew Schwartz wrote:
>>>>> On 4/27/26 11:09 AM, Gal Pressman wrote:
>>>>> Hello Matthew,
>>>>>
>>>>> On 27/04/2026 2:20, Matthew Schwartz wrote:
>>>>>> Hello,
>>>>>>
>>>>>> When using a previously working setup of remote streaming from my workstation to another device via Sunshine (the host server) and Moonlight (the client app) on my home network, I no longer receive any video output on the client app after upgrading my host workstation to kernel 7.0. Reverting back to kernel 6.19 on the host restored my setup to a working state.
>>>>>>
>>>>>> After bisecting, I landed on 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL") as the first bad commit. I confirmed this by moving the cable to my second on-board NIC (Intel) on the same workstation, which restored video output without any other kernel changes. My affected on-board NIC is Aquantia AQC113 [1d6a:04c0] (rev 03), atlantic driver, firmware 1.3.34, MTU 1500.
>>>>>>
>>>>>> Looking into it a bit further, ethtool -K enp97s0 tx-udp-segmentation off also serves as a workaround on my Aquantia port without changing to my other ethernet port. The working Intel NIC reports tx-udp-segmentation as "off [fixed]", so traffic falls back to software UDP segmentation on there.
>>>>>>
>>>>>> Please let me know if there's any additional info I can provide.
>>>>>>
>>>>>> Thanks,
>>>>>> Matt
>>>>>>
>>>>>> #regzbot introduced: 5b4015ad833c
>>>>>
>>>>> Thank you for the report and the bisect!
>>>>>
>>>>> I will take a look and try to figure out what's wrong (though I don't
>>>>> have real hardware to test on).
>>>>> Is the userspace app open source? can I see its code and try to run it
>>>>> myself?
>>>>
>>>> Thanks for the reply. The code for Sunshine is available here: https://github.com/LizardByte/Sunshine and the code for Moonlight is here: https://github.com/moonlight-stream/moonlight-qt.
>>>>
>>>> I have been using the Arch Linux Sunshine package which I installed by following the Linux instructions here: https://docs.lizardbyte.dev/projects/sunshine/latest/md_docs_2getting__started.html, but there are also binaries for other distros or it's buildable from source. For Moonlight, I have been using the Flatpak distributed on Flathub because the client device runs an atomic rootfs, but you can also use any other device that Moonlight supports.
>>>>
>>>>>
>>>>> I will be OOO for the rest of the week, hope to have some meaningful
>>>>> reply by the end of next week.
>>>>
>>>
>>> I think I see the issue, do you mind testing the following diff?
>>
>> Sorry for the delay. I applied this diff and I’m able to stream from my host to clients again without any issues.
>>
>> If you send this version upstream, feel free to add my Tested-by to it.
> 
> Thanks for verifying!
> 
> I will finalize this and submit a proper patch soon.

Hey Matthew,

I made a small change to the patch, can you please verify it still fixes
the issue?

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index a0813d425b71..71df45f9488a 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -604,7 +604,7 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 		       seg->data_len);
 	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);

-	uh->len = newlen;
+	uh->len = skb_is_gso(seg) ? msslen : newlen;
 	uh->check = check;

 	if (seg->ip_summed == CHECKSUM_PARTIAL)

Re: [REGRESSION] aquantia: Sunshine/Moonlight UDP video streaming broken since 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL")

[Matthew Schwartz]

On 5/10/26 5:38 AM, Gal Pressman wrote:
> On 06/05/2026 17:20, Gal Pressman wrote:
>> On 06/05/2026 10:49, Matthew Schwartz wrote:
>>>
>>>
>>>> On May 5, 2026, at 8:05 AM, Gal Pressman <gal@nvidia.com> wrote:
>>>>
>>>> On 27/04/2026 21:26, Matthew Schwartz wrote:
>>>>>> On 4/27/26 11:09 AM, Gal Pressman wrote:
>>>>>> Hello Matthew,
>>>>>>
>>>>>> On 27/04/2026 2:20, Matthew Schwartz wrote:
>>>>>>> Hello,
>>>>>>>
>>>>>>> When using a previously working setup of remote streaming from my workstation to another device via Sunshine (the host server) and Moonlight (the client app) on my home network, I no longer receive any video output on the client app after upgrading my host workstation to kernel 7.0. Reverting back to kernel 6.19 on the host restored my setup to a working state.
>>>>>>>
>>>>>>> After bisecting, I landed on 5b4015ad833c ("net: aquantia: Remove redundant UDP length adjustment with GSO_PARTIAL") as the first bad commit. I confirmed this by moving the cable to my second on-board NIC (Intel) on the same workstation, which restored video output without any other kernel changes. My affected on-board NIC is Aquantia AQC113 [1d6a:04c0] (rev 03), atlantic driver, firmware 1.3.34, MTU 1500.
>>>>>>>
>>>>>>> Looking into it a bit further, ethtool -K enp97s0 tx-udp-segmentation off also serves as a workaround on my Aquantia port without changing to my other ethernet port. The working Intel NIC reports tx-udp-segmentation as "off [fixed]", so traffic falls back to software UDP segmentation on there.
>>>>>>>
>>>>>>> Please let me know if there's any additional info I can provide.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Matt
>>>>>>>
>>>>>>> #regzbot introduced: 5b4015ad833c
>>>>>>
>>>>>> Thank you for the report and the bisect!
>>>>>>
>>>>>> I will take a look and try to figure out what's wrong (though I don't
>>>>>> have real hardware to test on).
>>>>>> Is the userspace app open source? can I see its code and try to run it
>>>>>> myself?
>>>>>
>>>>> Thanks for the reply. The code for Sunshine is available here: https://github.com/LizardByte/Sunshine and the code for Moonlight is here: https://github.com/moonlight-stream/moonlight-qt.
>>>>>
>>>>> I have been using the Arch Linux Sunshine package which I installed by following the Linux instructions here: https://docs.lizardbyte.dev/projects/sunshine/latest/md_docs_2getting__started.html, but there are also binaries for other distros or it's buildable from source. For Moonlight, I have been using the Flatpak distributed on Flathub because the client device runs an atomic rootfs, but you can also use any other device that Moonlight supports.
>>>>>
>>>>>>
>>>>>> I will be OOO for the rest of the week, hope to have some meaningful
>>>>>> reply by the end of next week.
>>>>>
>>>>
>>>> I think I see the issue, do you mind testing the following diff?
>>>
>>> Sorry for the delay. I applied this diff and I’m able to stream from my host to clients again without any issues.
>>>
>>> If you send this version upstream, feel free to add my Tested-by to it.
>>
>> Thanks for verifying!
>>
>> I will finalize this and submit a proper patch soon.
> 
> Hey Matthew,
> 
> I made a small change to the patch, can you please verify it still fixes
> the issue?

Yes, this diff also fixes the issue.

> 
> diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
> index a0813d425b71..71df45f9488a 100644
> --- a/net/ipv4/udp_offload.c
> +++ b/net/ipv4/udp_offload.c
> @@ -604,7 +604,7 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
>  		       seg->data_len);
>  	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
> 
> -	uh->len = newlen;
> +	uh->len = skb_is_gso(seg) ? msslen : newlen;
>  	uh->check = check;
> 
>  	if (seg->ip_summed == CHECKSUM_PARTIAL)