Cosmin Ratiu 53110232c9 net/mlx5: Don't zero user_count when destroying FDB tables
esw->user_count tracks how many TC rules are added on an esw via
mlx5e_configure_flower -> mlx5_esw_get -> atomic64_inc(&esw->user_count)

esw.user_count was unconditionally set to 0 in
esw_destroy_legacy_fdb_table and esw_destroy_offloads_fdb_tables.

These two together can lead to the following sequence of events:
1. echo 1 > /sys/class/net/eth2/device/sriov_numvfs
  - mlx5_core_sriov_configure -...-> esw_create_legacy_table ->
    atomic64_set(&esw->user_count, 0)
2. tc qdisc add dev eth2 ingress && \
   tc filter replace dev eth2 pref 1 protocol ip chain 0 ingress \
       handle 1 flower action ct nat zone 64000 pipe
  - mlx5e_configure_flower -> mlx5_esw_get ->
    atomic64_inc(&esw->user_count)
3. echo 0 > /sys/class/net/eth2/device/sriov_numvfs
  - mlx5_core_sriov_configure -..-> esw_destroy_legacy_fdb_table
    -> atomic64_set(&esw->user_count, 0)
4. devlink dev eswitch set pci/0000:08:00.0 mode switchdev
  - mlx5_devlink_eswitch_mode_set -> mlx5_esw_try_lock ->
    atomic64_read(&esw->user_count) == 0
  - then proceed to a WARN_ON in:
  esw_offloads_start -> mlx5_eswitch_enable_locke -> esw_offloads_enable
  -> mlx5_esw_offloads_rep_load -> mlx5e_vport_rep_load ->
  mlx5e_netdev_change_profile -> mlx5e_detach_netdev ->
  mlx5e_cleanup_nic_rx -> mlx5e_tc_nic_cleanup ->
  mlx5e_mod_hdr_tbl_destroy

Fix this by not clearing out the user_count when destroying FDB tables,
so that the check in mlx5_esw_try_lock can prevent the mode change when
there are TC rules configured, as originally intended.

Fixes: 2318b8bb94 ("net/mlx5: E-switch, Destroy legacy fdb table when needed")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/1761510019-938772-1-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 17:53:37 -07:00
2025-10-29 17:44:28 -07:00
2025-10-17 13:02:22 +02:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-10-19 15:19:16 -10:00
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.
Description
No description provided
Readme 3.5 GiB
Languages
C 97%
Assembly 1%
Shell 0.6%
Rust 0.5%
Python 0.4%
Other 0.3%