Re: [Intel-wired-lan] [PATCH iwl-net] idpf: protect shutdown from reset

[Simon Horman <horms@kernel.org>]

On Thu, Apr 10, 2025 at 01:52:23PM +0200, Larysa Zaremba wrote:
> Before the referenced commit, the shutdown just called idpf_remove(),
> this way IDPF_REMOVE_IN_PROG was protecting us from the serv_task
> rescheduling reset. Without this flag set the shutdown process is
> vulnerable to HW reset or any other triggering conditions (such as
> default mailbox being destroyed).
> 
> When one of conditions checked in idpf_service_task becomes true,
> vc_event_task can be rescheduled during shutdown, this leads to accessing
> freed memory e.g. idpf_req_rel_vector_indexes() trying to read
> vport->q_vector_idxs. This in turn causes the system to become defunct
> during e.g. systemctl kexec.
> 
> Considering using IDPF_REMOVE_IN_PROG would lead to more heavy shutdown
> process, instead just cancel the serv_task before cancelling
> adapter->serv_task before cancelling adapter->vc_event_task to ensure that
> reset will not be scheduled while we are doing a shutdown.
> 
> Fixes: 4c9106f4906a ("idpf: fix adapter NULL pointer dereference on reboot")
> Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>