mainlining shenanigans
cbb56b03ec
This simple script:
ip link add br0 type bridge
ip link set swp2 master br0
ip link set br0 address 00:01:02:03:04:05
ip link del br0
produces this result on a DSA switch:
[ 421.306399] br0: port 1(swp2) entered blocking state
[ 421.311445] br0: port 1(swp2) entered disabled state
[ 421.472553] device swp2 entered promiscuous mode
[ 421.488986] device swp2 left promiscuous mode
[ 421.493508] br0: port 1(swp2) entered disabled state
[ 421.886107] sja1105 spi0.1: port 1 failed to delete 00:01:02:03:04:05 vid 1 from fdb: -ENOENT
[ 421.894374] sja1105 spi0.1: port 1 failed to delete 00:01:02:03:04:05 vid 0 from fdb: -ENOENT
[ 421.943982] br0: port 1(swp2) entered blocking state
[ 421.949030] br0: port 1(swp2) entered disabled state
[ 422.112504] device swp2 entered promiscuous mode
A very simplified view of what happens is:
(1) the bridge port is created, and the bridge device inherits its MAC
address
(2) when joining, the bridge port (DSA) requests a replay of the
addition of all FDB entries towards this bridge port and towards the
bridge device itself. In fact, DSA calls br_fdb_replay() twice:
br_fdb_replay(br, brport_dev);
br_fdb_replay(br, br);
DSA uses reference counting for the FDB entries. So the MAC address
of the bridge is simply kept with refcount 2. When the bridge port
leaves under normal circumstances, everything cancels out since the
replay of the FDB entry deletion is also done twice per VLAN.
(3) when the bridge MAC address changes, switchdev is notified of the
deletion of the old address and of the insertion of the new one.
But the old address does not really go away, since it had refcount
2, and the new address is added "only" with refcount 1.
(4) when the bridge port leaves now, it will replay a deletion of the
FDB entries pointing towards the bridge twice. Then DSA will
complain that it can't delete something that no longer exists.
It is clear that the problem is that the FDB entries towards the bridge
are replayed too many times, so let's fix that problem.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 Restructured Text 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.