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Vladimir Oltean 0251e13f3f net: dsa: sja1105: discard incoming frames in BR_STATE_LISTENING
[ Upstream commit 498625a8ab ]

It has been reported that when under a bridge with stp_state=1, the logs
get spammed with this message:

[  251.734607] fsl_dpaa2_eth dpni.5 eth0: Couldn't decode source port

Further debugging shows the following info associated with packets:
source_port=-1, switch_id=-1, vid=-1, vbid=1

In other words, they are data plane packets which are supposed to be
decoded by dsa_tag_8021q_find_port_by_vbid(), but the latter (correctly)
refuses to do so, because no switch port is currently in
BR_STATE_LEARNING or BR_STATE_FORWARDING - so the packet is effectively
unexpected.

The error goes away after the port progresses to BR_STATE_LEARNING in 15
seconds (the default forward_time of the bridge), because then,
dsa_tag_8021q_find_port_by_vbid() can correctly associate the data plane
packets with a plausible bridge port in a plausible STP state.

Re-reading IEEE 802.1D-1990, I see the following:

"4.4.2 Learning: (...) The Forwarding Process shall discard received
frames."

IEEE 802.1D-2004 further clarifies:

"DISABLED, BLOCKING, LISTENING, and BROKEN all correspond to the
DISCARDING port state. While those dot1dStpPortStates serve to
distinguish reasons for discarding frames, the operation of the
Forwarding and Learning processes is the same for all of them. (...)
LISTENING represents a port that the spanning tree algorithm has
selected to be part of the active topology (computing a Root Port or
Designated Port role) but is temporarily discarding frames to guard
against loops or incorrect learning."

Well, this is not what the driver does - instead it sets
mac[port].ingress = true.

To get rid of the log spam, prevent unexpected data plane packets to
be received by software by discarding them on ingress in the LISTENING
state.

In terms of blame attribution: the prints only date back to commit
d7f9787a76 ("net: dsa: tag_8021q: add support for imprecise RX based
on the VBID"). However, the settings would permit a LISTENING port to
forward to a FORWARDING port, and the standard suggests that's not OK.

Fixes: 640f763f98 ("net: dsa: sja1105: Add support for Spanning Tree Protocol")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20250509113816.2221992-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-05-22 14:29:41 +02:00
arch KVM: x86/mmu: Prevent installing hugepages when mem attributes are changing 2025-05-22 14:29:36 +02:00
block blk-mq: create correct map for fallback case 2025-05-09 09:50:48 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: Kconfig - Select LIB generic option 2025-05-02 07:59:33 +02:00
Documentation x86/its: Add support for RSB stuffing mitigation 2025-05-18 08:24:59 +02:00
drivers net: dsa: sja1105: discard incoming frames in BR_STATE_LISTENING 2025-05-22 14:29:41 +02:00
fs nfs: handle failure of nfs_get_lock_context in unlock path 2025-05-22 14:29:38 +02:00
include ALSA: ump: Fix a typo of snd_ump_stream_msg_device_info 2025-05-22 14:29:41 +02:00
init rust: clean Rust 1.88.0's unnecessary_transmutes lint 2025-05-18 08:24:51 +02:00
io_uring io_uring: always arm linked timeouts prior to issue 2025-05-18 08:24:57 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel tracing: probes: Fix a possible race in trace_probe_log APIs 2025-05-22 14:29:36 +02:00
lib crypto: lib/Kconfig - Hide arch options from user 2025-05-02 07:59:32 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: page_alloc: speed up fallbacks in rmqueue_bulk() 2025-05-18 08:24:57 +02:00
net net: mctp: Ensure keys maintain only one ref to corresponding dev 2025-05-22 14:29:40 +02:00
rust rust: clean Rust 1.88.0's clippy::uninlined_format_args lint 2025-05-18 08:24:57 +02:00
samples tracing: Verify event formats that have "%*p.." 2025-05-02 07:58:52 +02:00
scripts objtool: Silence more KCOV warnings, part 2 2025-05-02 07:59:33 +02:00
security landlock: Prepare to add second errata 2025-04-20 10:15:56 +02:00
sound ALSA: seq: Fix delivery of UMP events to group ports 2025-05-22 14:29:40 +02:00
tools tests/ncdevmem: Fix double-free of queue array 2025-05-22 14:29:40 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Add member to struct kvm_gfn_range to indicate private/shared 2025-05-22 14:29:36 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-18 08:24:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add entry for the Rust alloc module 2025-03-13 13:01:47 +01:00
Makefile Linux 6.12.29 2025-05-18 08:25:00 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

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

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.