On Friday 20 July 2012 09:23:15 Dan Carpenter wrote:
> On Thu, Jul 19, 2012 at 02:29:41PM +0200, Christian Lamparter wrote:
> > Hello Dan,
> >
> > On Thu, Jul 19, 2012 at 1:36 PM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> > > Sorry this is so old. I was going through some old Smatch warnings.
> > >
> > > This is a semi-automatic email about new static checker warnings.
> > >
> > > The patch caf1eae20668: "carl9170: improve unicast PS buffering" from
> > > Apr 24, 2011, leads to the following Smatch complaint:
> > >
> > > drivers/net/wireless/ath/carl9170/tx.c:1488 carl9170_op_tx()
> > > error: we previously assumed 'sta' could be null (see line 1482)
> > >
> > > drivers/net/wireless/ath/carl9170/tx.c
> > > 1481
> > > 1482 if (sta) {
> > > ^^^^^
> > > New check.
> > >
> > > 1483 struct carl9170_sta_info *stai = (void *) sta->drv_priv;
> > > 1484 atomic_inc(&stai->pending_frames);
> > > 1485 }
> > > 1486
> > > 1487 if (info->flags & IEEE80211_TX_CTL_AMPDU) {
> > > 1488 run = carl9170_tx_ampdu_queue(ar, sta, skb);
> > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > Old dereference of "sta" inside the call to carl9170_tx_ampdu_queue().
> > >
> > > 1489 if (run)
> > > 1490 carl9170_tx_ampdu(ar);
> > >
> > > Probably we can remove the check?
> > What check do you want to remove? The check in smatch
> > which produces the warning/error. Or the "if (sta) {" in line
> > 1482?
> >
> > Or do you mean I should extend the check in 1487 to:
> > if (sta) {
> > ...
> > if (info->flags & IEEE80211_TX_CTL_AMPDU) {
> > ....
> > }
> > }
>
> What I'm saying is that I don't ?know? if it's possible
> for "sta" to be NULL at this pointer or not.
no, it is not possible.
In fact, in order to set up a ampdu session, the stack would
call the driver's op_ampdu_action callback which always needs
a station.
Regards,
Chr
(So, where do we go from here - do you still want a patch?)
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