CVE-2026-45973

In the Linux kernel, the following vulnerability has been resolved:

RDMA/mlx5: Fix UMR hang in LAG error state unload

During firmware reset in LAG mode, a race condition causes the driver

to hang indefinitely while waiting for UMR completion during device

unload. See [1].

In LAG mode the bond device is only registered on the master, so it

never sees sys_error events from the slave.

During firmware reset this causes UMR waits to hang forever on unload

as the slave is dead but the master hasn't entered error state yet, so

UMR posts succeed but completions never arrive.

Fix this by adding a sys_error notifier that gets registered before

MLX5_IB_STAGE_IB_REG and stays alive until after ib_unregister_device().

This ensures error events reach the bond device throughout teardown.

[1]

Call Trace:

__schedule+0x2bd/0x760

schedule+0x37/0xa0

schedule_preempt_disabled+0xa/0x10

__mutex_lock.isra.6+0x2b5/0x4a0

__mlx5_ib_dereg_mr+0x606/0x870 [mlx5_ib]

? __xa_erase+0x4a/0xa0

? _cond_resched+0x15/0x30

? wait_for_completion+0x31/0x100

ib_dereg_mr_user+0x48/0xc0 [ib_core]

? rdmacg_uncharge_hierarchy+0xa0/0x100

destroy_hw_idr_uobject+0x20/0x50 [ib_uverbs]

uverbs_destroy_uobject+0x37/0x150 [ib_uverbs]

__uverbs_cleanup_ufile+0xda/0x140 [ib_uverbs]

uverbs_destroy_ufile_hw+0x3a/0xf0 [ib_uverbs]

ib_uverbs_remove_one+0xc3/0x140 [ib_uverbs]

remove_client_context+0x8b/0xd0 [ib_core]

disable_device+0x8c/0x130 [ib_core]

__ib_unregister_device+0x10d/0x180 [ib_core]

ib_unregister_device+0x21/0x30 [ib_core]

__mlx5_ib_remove+0x1e4/0x1f0 [mlx5_ib]

auxiliary_bus_remove+0x1e/0x30

device_release_driver_internal+0x103/0x1f0

bus_remove_device+0xf7/0x170

device_del+0x181/0x410

mlx5_rescan_drivers_locked.part.10+0xa9/0x1d0 [mlx5_core]

mlx5_disable_lag+0x253/0x260 [mlx5_core]

mlx5_lag_disable_change+0x89/0xc0 [mlx5_core]

mlx5_eswitch_disable+0x67/0xa0 [mlx5_core]

mlx5_unload+0x15/0xd0 [mlx5_core]

mlx5_unload_one+0x71/0xc0 [mlx5_core]

mlx5_sync_reset_reload_work+0x83/0x100 [mlx5_core]

process_one_work+0x1a7/0x360

worker_thread+0x30/0x390

? create_worker+0x1a0/0x1a0

kthread+0x116/0x130

? kthread_flush_work_fn+0x10/0x10

ret_from_fork+0x22/0x40