[bug report] iwlwifi: mvm: Explicitly stop session protection before unbinding

[bug report] iwlwifi: mvm: Explicitly stop session protection before unbinding

[Dan Carpenter]

Hello Ilan Peer,

This is a semi-automatic email about new static checker warnings.

The patch 7b3954a1d69a: "iwlwifi: mvm: Explicitly stop session 
protection before unbinding" from Jun 18, 2021, leads to the 
following Smatch complaint:

    drivers/net/wireless/intel/iwlwifi/mvm/time-event.c:668 __iwl_mvm_remove_time_event()
    warn: variable dereferenced before check 'te_data->vif' (see line 665)

drivers/net/wireless/intel/iwlwifi/mvm/time-event.c
   664		u32 id;
   665		struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(te_data->vif);
                                                                       ^^^^^^^^^^^^
This is dereferenced inside the function.

   666		enum nl80211_iftype iftype;
   667	
   668		if (!te_data->vif)
                    ^^^^^^^^^^^^^
The new patch adds a check for NULL, but I don't think it is required.
The kernel would have already crashed at this point at any rate so the
dereference needs to be moved.

   669			return false;
   670	
   671          iftype = te_data->vif->type;
   672  
   673          /*
   674           * It is possible that by the time we got to this point the time
   675           * event was already removed.


regards,
dan carpenter

RE: [bug report] iwlwifi: mvm: Explicitly stop session protection before unbinding

[Peer, Ilan]

Hi Dan,

I'll prepare a fix for this.

Thanks,

Ilan.

> -----Original Message-----
> From: Dan Carpenter <dan.carpenter@oracle.com>
> Sent: Tuesday, August 31, 2021 10:43
> To: Peer, Ilan <ilan.peer@intel.com>
> Cc: linux-wireless@vger.kernel.org
> Subject: [bug report] iwlwifi: mvm: Explicitly stop session protection before
> unbinding
> 
> Hello Ilan Peer,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> The patch 7b3954a1d69a: "iwlwifi: mvm: Explicitly stop session protection
> before unbinding" from Jun 18, 2021, leads to the following Smatch
> complaint:
> 
>     drivers/net/wireless/intel/iwlwifi/mvm/time-event.c:668
> __iwl_mvm_remove_time_event()
>     warn: variable dereferenced before check 'te_data->vif' (see line 665)
> 
> drivers/net/wireless/intel/iwlwifi/mvm/time-event.c
>    664		u32 id;
>    665		struct iwl_mvm_vif *mvmvif =
> iwl_mvm_vif_from_mac80211(te_data->vif);
>                                                                        ^^^^^^^^^^^^ This is dereferenced
> inside the function.
> 
>    666		enum nl80211_iftype iftype;
>    667
>    668		if (!te_data->vif)
>                     ^^^^^^^^^^^^^
> The new patch adds a check for NULL, but I don't think it is required.
> The kernel would have already crashed at this point at any rate so the
> dereference needs to be moved.
> 
>    669			return false;
>    670
>    671          iftype = te_data->vif->type;
>    672
>    673          /*
>    674           * It is possible that by the time we got to this point the time
>    675           * event was already removed.
> 
> 
> regards,
> dan carpenter