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Vladimir Oltean
0b0e2ff103
When the DSA_NOTIFIER_TAG_PROTO returns an error, the user space process
which initiated the protocol change exits the kernel processing while
still holding the rtnl_mutex. So any other process attempting to lock
the rtnl_mutex would deadlock after such event.
The error handling of DSA_NOTIFIER_TAG_PROTO was inadvertently changed
by the blamed commit, introducing this regression. We must still call
rtnl_unlock(), and we must still call DSA_NOTIFIER_TAG_PROTO for the old
protocol. The latter is due to the limiting design of notifier chains
for cross-chip operations, which don't have a built-in error recovery
mechanism - we should look into using notifier_call_chain_robust for that.
Fixes: dc452a471d ("net: dsa: introduce tagger-owned storage for private and shared data")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220228141715.146485-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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.