2015-01-19 14:52:50

by Dan Carpenter

[permalink] [raw]
Subject: re: wil6210: ADDBA/DELBA flows

Hello Vladimir Kondratiev,

The patch 3277213feb1b: "wil6210: ADDBA/DELBA flows" from Dec 23,
2014, leads to the following static checker warning:

drivers/net/wireless/ath/wil6210/rx_reorder.c:205 wil_tid_ampdu_rx_alloc()
error: scheduling with locks held: 'spin_lock:tid_rx_lock'

drivers/net/wireless/ath/wil6210/rx_reorder.c
202 struct wil_tid_ampdu_rx *wil_tid_ampdu_rx_alloc(struct wil6210_priv *wil,
203 int size, u16 ssn)
204 {
205 struct wil_tid_ampdu_rx *r = kzalloc(sizeof(*r), GFP_KERNEL);
^^^^^^^^^^
206
207 if (!r)
208 return NULL;
209
210 r->reorder_buf =
211 kcalloc(size, sizeof(struct sk_buff *), GFP_KERNEL);
^^^^^^^^^^^
212 r->reorder_time =
213 kcalloc(size, sizeof(unsigned long), GFP_KERNEL);
^^^^^^^^^^^
214 if (!r->reorder_buf || !r->reorder_time) {
215 kfree(r->reorder_buf);
216 kfree(r->reorder_time);
217 kfree(r);
218 return NULL;
219 }
220

[ snip ]

331 spin_lock_bh(&sta->tid_rx_lock);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
spin lock held.

332
333 wil_tid_ampdu_rx_free(wil, sta->tid_rx[tid]);
334 sta->tid_rx[tid] = wil_tid_ampdu_rx_alloc(wil, agg_wsize, ssn);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
function called with the lock held.

335
336 spin_unlock_bh(&sta->tid_rx_lock);

This looks like it would be pretty easy to re-write so the allocation
was done before we take the lock if someone knew exactly what the lock
was protecting.

regards,
dan carpenter


2015-01-20 10:14:59

by Vladimir Kondratiev

[permalink] [raw]
Subject: Re: wil6210: ADDBA/DELBA flows

On Monday, January 19, 2015 05:53:32 PM Dan Carpenter wrote:
> The patch 3277213feb1b: "wil6210: ADDBA/DELBA flows" from Dec 23,
> 2014, leads to the following static checker warning:
>
> drivers/net/wireless/ath/wil6210/rx_reorder.c:205 wil_tid_ampdu_rx_alloc()
> error: scheduling with locks held: 'spin_lock:tid_rx_lock'
>

Dan, thanks for finding this. Will submit patch shortly

Thanks, Vladimir