net/mlx5e: Fix deadlocks between devlink and netdev instance locks
authorCosmin Ratiu <cratiu@nvidia.com>
Wed, 18 Feb 2026 07:29:03 +0000 (09:29 +0200)
committerJakub Kicinski <kuba@kernel.org>
Thu, 19 Feb 2026 17:30:16 +0000 (09:30 -0800)
commit83ac0304a2d77519dae1e54c9713cbe1aedf19c9
treec0eae92a12d861d7a8a479dde2a12149e4c93d28
parent9854b243ce4225328d0b32fdc998d35b6952d3f7
net/mlx5e: Fix deadlocks between devlink and netdev instance locks

In the mentioned "Fixes" commit, various work tasks triggering devlink
health reporter recovery were switched to use netdev_trylock to protect
against concurrent tear down of the channels being recovered. But this
had the side effect of introducing potential deadlocks because of
incorrect lock ordering.

The correct lock order is described by the init flow:
probe_one -> mlx5_init_one (acquires devlink lock)
-> mlx5_init_one_devl_locked -> mlx5_register_device
-> mlx5_rescan_drivers_locked -...-> mlx5e_probe -> _mlx5e_probe
-> register_netdev (acquires rtnl lock)
-> register_netdevice (acquires netdev lock)
=> devlink lock -> rtnl lock -> netdev lock.

But in the current recovery flow, the order is wrong:
mlx5e_tx_err_cqe_work (acquires netdev lock)
-> mlx5e_reporter_tx_err_cqe -> mlx5e_health_report
-> devlink_health_report (acquires devlink lock => boom!)
-> devlink_health_reporter_recover
-> mlx5e_tx_reporter_recover -> mlx5e_tx_reporter_recover_from_ctx
-> mlx5e_tx_reporter_err_cqe_recover

The same pattern exists in:
mlx5e_reporter_rx_timeout
mlx5e_reporter_tx_ptpsq_unhealthy
mlx5e_reporter_tx_timeout

Fix these by moving the netdev_trylock calls from the work handlers
lower in the call stack, in the respective recovery functions, where
they are actually necessary.

Fixes: 8f7b00307bf1 ("net/mlx5e: Convert mlx5 netdevs to instance locking")
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: Jacob Keller <Jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260218072904.1764634-6-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
drivers/net/ethernet/mellanox/mlx5/core/en/reporter_rx.c
drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c
drivers/net/ethernet/mellanox/mlx5/core/en_main.c