[PATCH] ath10k: fix potential null dereference bugs

[Michal Kazior]

On 10 June 2016 at 14:52, Bob Copeland <me at bobcopeland.com> wrote:
> Smatch warns about a number of cases in ath10k where a pointer is
> null-checked after it has already been dereferenced, in code involving
> ath10k private virtual interface pointers.
>
> Fix these by making the dereference happen later.
>
> Addresses the following smatch warnings:
>
> drivers/net/wireless/ath/ath10k/mac.c:3651 ath10k_mac_txq_init() warn: variable dereferenced before check 'txq' (see line 3649)
> drivers/net/wireless/ath/ath10k/mac.c:3664 ath10k_mac_txq_unref() warn: variable dereferenced before check 'txq' (see line 3659)
> drivers/net/wireless/ath/ath10k/htt_tx.c:70 __ath10k_htt_tx_txq_recalc() warn: variable dereferenced before check 'txq->sta' (see line 52)
> drivers/net/wireless/ath/ath10k/htt_tx.c:740 ath10k_htt_tx_get_vdev_id() warn: variable dereferenced before check 'cb->vif' (see line 736)
> drivers/net/wireless/ath/ath10k/txrx.c:86 ath10k_txrx_tx_unref() warn: variable dereferenced before check 'txq' (see line 84)
> drivers/net/wireless/ath/ath10k/wmi.c:1837 ath10k_wmi_op_gen_mgmt_tx() warn: variable dereferenced before check 'cb->vif' (see line 1825)

FWIW all of these are false positives. I think this was already
pointed out some time ago. The drv_priv stuff is merely an offset (see
how ieee80211_vif and ieee80211_sta are defined) and the according
structure is always checked beforehand.


Michał