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Jakub Kicinski d4bfe16cbd Merge branch 'net-stmmac-fix-double-vlan-802-1ad-tag-handling'
Ovidiu Panait says:

====================
net: stmmac: Fix double VLAN 802.1ad tag handling

Currently, hardware VLAN stripping is broken for 802.1ad tags. vlan_rx_hw()
hardcodes ETH_P_8021Q when putting the hardware tag into the skb, rather
than using the actual protocol from the packet. Because of this, packets
that contain an 802.1ad outer tag are incorrectly passed up the stack as
having an 802.1Q tag.

This issue was observed on the Renesas RZ/V2H platform (which has a dwmac4
IP), when testing QinQ ping:

  # DUT
  ip link add link end0 name end0.100 type vlan proto 802.1ad id 100
  ip link add link end0.100 name end0.100.200 type vlan proto 802.1q id 200
  ip addr add 172.16.3.2/24 dev end0.100.200
  ip link set end0 up
  ip link set end0.100 up
  ip link set end0.100.200 up

  # Peer
  ip link add link eth0 name eth0.100 type vlan proto 802.1ad id 100
  ip link add link eth0.100 name eth0.100.200 type vlan proto 802.1q id 200
  ip addr add 172.16.3.1/24 dev eth0.100.200
  ip link set eth0 up
  ip link set eth0.100 up
  ip link set eth0.100.200 up
  ping 172.16.3.2
    -- FAIL --

Note that this series only fixes the issue on dwmac4. dwxgmac2 has the same
issue but I do not have access to hw to test on.

Since dwmac4 does not expose the tag type in the RDES3 descriptor, it
cannot support hardware S-Tag stripping correctly. This series
disables S-tag stripping for it, so the 802.1ad tags are left in
place and are handled by the software VLAN path.
====================

Link: https://patch.msgid.link/20260928203441.34876-1-ovidiu.panait.rb@renesas.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
History 2026-10-05 16:36:45 -07:00
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Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
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* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
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* License: See COPYING

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https://www.kernel.org/doc/html/latest/


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============

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* New Kernel Developer: Getting started with kernel development
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For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
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* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
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* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
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---------------

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* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

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--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
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* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
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----------

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* Maintainer Handbook: Documentation/maintainer/index.rst
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---------------

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* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


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=========================

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