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Daniel Borkmann eef51113f8 netkit: Add netkit notifier to check for unregistering devices
Add a netdevice notifier in netkit to watch for NETDEV_UNREGISTER events.
If the target device is indeed NETREG_UNREGISTERING and previously leased
a queue to a netkit device, then collect the related netkit devices and
batch-unregister_netdevice_many() them.

If this would not be done, then the netkit device would hold a reference
on the physical device preventing it from going away. However, in case of
both io_uring zero-copy as well as AF_XDP this situation is handled
gracefully and the allocated resources are torn down.

In the case where mentioned infra is used through netkit, the applications
have a reference on netkit, and netkit in turn holds a reference on the
physical device. In order to have netkit release the reference on the
physical device, we need such watcher to then unregister the netkit ones.

This is generally quite similar to the dependency handling in case of
tunnels (e.g. vxlan bound to a underlying netdev) where the tunnel device
gets removed along with the physical device.

  # ip a
  [...]
  4: enp10s0f0np0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
      link/ether e8:eb:d3:a3:43:f6 brd ff:ff:ff:ff:ff:ff
      inet 10.0.0.2/24 scope global enp10s0f0np0
         valid_lft forever preferred_lft forever
  [...]
  8: nk@NONE: <BROADCAST,MULTICAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
      link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
  [...]

  # rmmod mlx5_ib
  # rmmod mlx5_core

  [  309.261822] mlx5_core 0000:0a:00.0 mlx5_0: Port: 1 Link DOWN
  [  344.235236] mlx5_core 0000:0a:00.1: E-Switch: Unload vfs: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
  [  344.246948] mlx5_core 0000:0a:00.1: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
  [  344.463754] mlx5_core 0000:0a:00.1: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
  [  344.770155] mlx5_core 0000:0a:00.1: E-Switch: cleanup
  [  345.345709] mlx5_core 0000:0a:00.0: E-Switch: Unload vfs: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
  [  345.357524] mlx5_core 0000:0a:00.0: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
  [  350.995989] mlx5_core 0000:0a:00.0: E-Switch: Disable: mode(LEGACY), nvfs(0), necvfs(0), active vports(0)
  [  351.574396] mlx5_core 0000:0a:00.0: E-Switch: cleanup

  # ip a
  [...]
  [ both enp10s0f0np0 and nk gone ]
  [...]

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: David Wei <dw@davidwei.uk>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260115082603.219152-12-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-01-20 11:58:50 +01:00
Documentation net: Add queue-create operation 2026-01-20 11:58:49 +01:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
arch net: ethernet: dnet: remove driver 2026-01-15 19:38:54 -08:00
block block-6.19-20260109 2026-01-09 15:42:46 -10:00
certs
crypto crypto: seqiv - Do not use req->iv after crypto_aead_encrypt 2025-12-19 14:47:06 +08:00
drivers netkit: Add netkit notifier to check for unregistering devices 2026-01-20 11:58:50 +01:00
fs gfs2 revert 2026-01-13 10:04:34 -08:00
include netkit: Add netkit notifier to check for unregistering devices 2026-01-20 11:58:50 +01:00
init Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
io_uring io_uring-6.19-20260109 2026-01-09 15:21:15 -10:00
ipc Significant patch series in this pull request: 2025-12-06 14:01:20 -08:00
kernel bpf-fixes 2026-01-13 21:21:13 -08:00
lib Crypto library fixes for v6.19-rc5 2026-01-11 15:07:56 -10:00
mm mm/ksm: fix pte_unmap_unlock of wrong address in break_ksm_pmd_entry 2025-12-23 11:23:17 -08:00
net xsk: Proxy pool management for leased queues 2026-01-20 11:58:50 +01:00
rust Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2026-01-15 18:02:48 -08:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2025-12-31 15:19:25 +08:00
scripts Crypto library fixes for v6.19-rc5 2026-01-11 15:07:56 -10:00
security kernel/kexec: change the prototype of kimage_map_segment() 2025-12-23 11:23:13 -08:00
sound ALSA: hda/realtek: add HP Laptop 15s-eq1xxx mute LED quirk 2026-01-02 14:34:23 +01:00
tools net: Add queue-create operation 2026-01-20 11:58:49 +01:00
usr initramfs: add gen_init_cpio to hostprogs unconditionally 2025-11-26 21:55:40 +01:00
virt KVM fixes for 6.19-rc1 2025-12-18 18:38:45 +01:00
.clang-format s390/pci: Fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices() 2025-12-14 11:03:58 +01:00
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore rust: kbuild: add proc macro library support 2025-11-24 17:15:36 +01:00
.mailmap treewide: Update email address 2026-01-11 06:09:11 -10:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml
COPYING
CREDITS treewide: Update email address 2026-01-11 06:09:11 -10:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig
MAINTAINERS phy common properties 2026-01-15 19:15:07 -08:00
Makefile Linux 6.19-rc5 2026-01-11 17:03:14 -10:00
README README: restructure with role-based documentation and guidelines 2025-11-29 08:40:33 -07:00

README

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
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

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

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros


For Specific Users
==================

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

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* 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
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* 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

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* 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



Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst