5e7695e021
Unlike ice, idpf does not check, if user has requested at least 1 combined
channel. Instead, it relies on a check in the core code. Unfortunately, the
check does not trigger for us because of the hacky .set_channels()
interpretation logic that is not consistent with the core code.
This naturally leads to user being able to trigger a crash with an invalid
input. This is how:
1. ethtool -l <IFNAME> -> combined: 40
2. ethtool -L <IFNAME> rx 0 tx 0
combined number is not specified, so command becomes {rx_count = 0,
tx_count = 0, combined_count = 40}.
3. ethnl_set_channels checks, if there is at least 1 RX and 1 TX channel,
comparing (combined_count + rx_count) and (combined_count + tx_count)
to zero. Obviously, (40 + 0) is greater than zero, so the core code
deems the input OK.
4. idpf interprets `rx 0 tx 0` as 0 channels and tries to proceed with such
configuration.
The issue has to be solved fundamentally, as current logic is also known to
cause AF_XDP problems in ice [0].
Interpret the command in a way that is more consistent with ethtool
manual [1] (--show-channels and --set-channels) and new ice logic.
Considering that in the idpf driver only the difference between RX and TX
queues forms dedicated channels, change the correct way to set number of
channels to:
ethtool -L <IFNAME> combined 10 /* For symmetric queues */
ethtool -L <IFNAME> combined 8 tx 2 rx 0 /* For asymmetric queues */
[0] https://lore.kernel.org/netdev/20240418095857.2827-1-larysa.zaremba@intel.com/
[1] https://man7.org/linux/man-pages/man8/ethtool.8.html
Fixes: 02cbfba1add5 ("idpf: add ethtool callbacks")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Igor Bagnucki <igor.bagnucki@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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.