Aditya Kumar Singh <quic_adisi@xxxxxxxxxxx> writes:
> On 8/6/24 17:58, Kalle Valo wrote:
>
>> Rameshkumar Sundaram <quic_ramess@xxxxxxxxxxx> writes:
>>
>>> From: Sriram R <quic_srirrama@xxxxxxxxxxx>
>>>
>>> To prepare the driver for MLO support, split the driver vif
>>> data structure to scale for multiple links. This requires changing
>>> the use of arvif to per link and not per hw which can now
>>> comprise of multiple links.
>>> Also since most configurations from mac80211 are done per link, do refactoring
>>> of the driver functions to apply these configurations at link level.
>> Something I noticed while reviewing this patchset:
>>
>>> static int ath12k_mac_op_add_interface(struct ieee80211_hw *hw,
>>> struct ieee80211_vif *vif)
>>> {
>>> - struct ath12k_vif *arvif = ath12k_vif_to_arvif(vif);
>>> + struct ath12k_hw *ah = ath12k_hw_to_ah(hw);
>>> + struct ath12k_vif *ahvif = ath12k_vif_to_ahvif(vif);
>>> + struct ath12k_link_vif *arvif;
>>> int i;
>>> - memset(arvif, 0, sizeof(*arvif));
>>> + mutex_lock(&ah->conf_mutex);
>>> + memset(ahvif, 0, sizeof(*ahvif));
>> Here we are we clearing ahvif so ahvif->deflink is NULL.
>
> deflink is not a pointer member. It is statically defined inside
> ahvif. So basically this memsets the whole deflink memory region to 0.
>>
>>> - arvif->vif = vif;
>>> + ahvif->ah = ah;
>>> + ahvif->vif = vif;
>>> + arvif = &ahvif->deflink;
>> So here we assign arvif to NULL.
>
> This would be a still valid pointer.
>>
>>> + arvif->ahvif = ahvif;
>> And because arvif is NULL this is a null pointer reference, right?
>> Or am
>> I missing something?
>
> So since it is valid pointer, this is not a NULL pointer de-reference.
Ah, of course. Clearly my vacation was too good and I forgot C :) Thanks!
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