diff mbox series

[3/8] staging: wfx: standardize the error when vif does not exist

Message ID 20201009171307.864608-4-Jerome.Pouiller@silabs.com
State New
Headers show
Series None | expand

Commit Message

Jérôme Pouiller Oct. 9, 2020, 5:13 p.m. UTC 
From: Jérôme Pouiller <jerome.pouiller@silabs.com>

Smatch complains:

   drivers/staging/wfx/hif_rx.c:177 hif_scan_complete_indication() warn: potential NULL parameter dereference 'wvif'
   drivers/staging/wfx/data_tx.c:576 wfx_flush() warn: potential NULL parameter dereference 'wvif'

Indeed, if the vif id returned by the device does not exist anymore,
wdev_to_wvif() could return NULL.

In add, the error is not handled uniformly in the code, sometime a
WARN() is displayed but code continue, sometime a dev_warn() is
displayed, sometime it is just not tested, ...

This patch standardize that.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
---
 drivers/staging/wfx/data_tx.c |  5 ++++-
 drivers/staging/wfx/hif_rx.c  | 34 ++++++++++++++++++++++++----------
 drivers/staging/wfx/sta.c     |  4 ++++
 3 files changed, 32 insertions(+), 11 deletions(-)

Comments

Kalle Valo Oct. 9, 2020, 6:52 p.m. UTC | #1 
Jerome Pouiller <Jerome.Pouiller@silabs.com> writes:

> From: Jérôme Pouiller <jerome.pouiller@silabs.com>
>
> Smatch complains:
>
>    drivers/staging/wfx/hif_rx.c:177 hif_scan_complete_indication() warn: potential NULL parameter dereference 'wvif'
>    drivers/staging/wfx/data_tx.c:576 wfx_flush() warn: potential NULL parameter dereference 'wvif'
>
> Indeed, if the vif id returned by the device does not exist anymore,
> wdev_to_wvif() could return NULL.
>
> In add, the error is not handled uniformly in the code, sometime a
> WARN() is displayed but code continue, sometime a dev_warn() is
> displayed, sometime it is just not tested, ...
>
> This patch standardize that.
>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
> ---
>  drivers/staging/wfx/data_tx.c |  5 ++++-
>  drivers/staging/wfx/hif_rx.c  | 34 ++++++++++++++++++++++++----------
>  drivers/staging/wfx/sta.c     |  4 ++++
>  3 files changed, 32 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
> index b4d5dd3d2d23..8db0be08daf8 100644
> --- a/drivers/staging/wfx/data_tx.c
> +++ b/drivers/staging/wfx/data_tx.c
> @@ -431,7 +431,10 @@ static void wfx_skb_dtor(struct wfx_vif *wvif, struct sk_buff *skb)
>  			      sizeof(struct hif_req_tx) +
>  			      req->fc_offset;
>  
> -	WARN_ON(!wvif);
> +	if (!wvif) {
> +		pr_warn("%s: vif associated with the skb does not exist anymore\n", __func__);
> +		return;
> +	}

I'm not really a fan of using function names in warning or error
messages as it clutters the log. In debug messages I think they are ok.
Jérôme Pouiller Oct. 10, 2020, 12:22 p.m. UTC | #2 
On Friday 9 October 2020 20:52:47 CEST Kalle Valo wrote:
> Jerome Pouiller <Jerome.Pouiller@silabs.com> writes:
> 
> > From: Jérôme Pouiller <jerome.pouiller@silabs.com>
> >
> > Smatch complains:
> >
> >    drivers/staging/wfx/hif_rx.c:177 hif_scan_complete_indication() warn: potential NULL parameter dereference 'wvif'
> >    drivers/staging/wfx/data_tx.c:576 wfx_flush() warn: potential NULL parameter dereference 'wvif'
> >
> > Indeed, if the vif id returned by the device does not exist anymore,
> > wdev_to_wvif() could return NULL.
> >
> > In add, the error is not handled uniformly in the code, sometime a
> > WARN() is displayed but code continue, sometime a dev_warn() is
> > displayed, sometime it is just not tested, ...
> >
> > This patch standardize that.
> >
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
> > ---
> >  drivers/staging/wfx/data_tx.c |  5 ++++-
> >  drivers/staging/wfx/hif_rx.c  | 34 ++++++++++++++++++++++++----------
> >  drivers/staging/wfx/sta.c     |  4 ++++
> >  3 files changed, 32 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
> > index b4d5dd3d2d23..8db0be08daf8 100644
> > --- a/drivers/staging/wfx/data_tx.c
> > +++ b/drivers/staging/wfx/data_tx.c
> > @@ -431,7 +431,10 @@ static void wfx_skb_dtor(struct wfx_vif *wvif, struct sk_buff *skb)
> >                             sizeof(struct hif_req_tx) +
> >                             req->fc_offset;
> >
> > -     WARN_ON(!wvif);
> > +     if (!wvif) {
> > +             pr_warn("%s: vif associated with the skb does not exist anymore\n", __func__);
> > +             return;
> > +     }
> 
> I'm not really a fan of using function names in warning or error
> messages as it clutters the log. In debug messages I think they are ok.

In the initial code, I used WARN() that far more clutters the log (I
have stated that a backtrace won't provide any useful information, so
pr_warn() was better suited).

In add, in my mind, these warnings are debug messages. If they appears,
the user should probably report a bug.

Finally, in this patch, I use the same message several times (ok, not
this particular one). So the function name is a way to differentiate
them.
Greg KH Oct. 10, 2020, 12:40 p.m. UTC | #3 
On Sat, Oct 10, 2020 at 02:22:13PM +0200, Jérôme Pouiller wrote:
> On Friday 9 October 2020 20:52:47 CEST Kalle Valo wrote:
> > Jerome Pouiller <Jerome.Pouiller@silabs.com> writes:
> > 
> > > From: Jérôme Pouiller <jerome.pouiller@silabs.com>
> > >
> > > Smatch complains:
> > >
> > >    drivers/staging/wfx/hif_rx.c:177 hif_scan_complete_indication() warn: potential NULL parameter dereference 'wvif'
> > >    drivers/staging/wfx/data_tx.c:576 wfx_flush() warn: potential NULL parameter dereference 'wvif'
> > >
> > > Indeed, if the vif id returned by the device does not exist anymore,
> > > wdev_to_wvif() could return NULL.
> > >
> > > In add, the error is not handled uniformly in the code, sometime a
> > > WARN() is displayed but code continue, sometime a dev_warn() is
> > > displayed, sometime it is just not tested, ...
> > >
> > > This patch standardize that.
> > >
> > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
> > > ---
> > >  drivers/staging/wfx/data_tx.c |  5 ++++-
> > >  drivers/staging/wfx/hif_rx.c  | 34 ++++++++++++++++++++++++----------
> > >  drivers/staging/wfx/sta.c     |  4 ++++
> > >  3 files changed, 32 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
> > > index b4d5dd3d2d23..8db0be08daf8 100644
> > > --- a/drivers/staging/wfx/data_tx.c
> > > +++ b/drivers/staging/wfx/data_tx.c
> > > @@ -431,7 +431,10 @@ static void wfx_skb_dtor(struct wfx_vif *wvif, struct sk_buff *skb)
> > >                             sizeof(struct hif_req_tx) +
> > >                             req->fc_offset;
> > >
> > > -     WARN_ON(!wvif);
> > > +     if (!wvif) {
> > > +             pr_warn("%s: vif associated with the skb does not exist anymore\n", __func__);
> > > +             return;
> > > +     }
> > 
> > I'm not really a fan of using function names in warning or error
> > messages as it clutters the log. In debug messages I think they are ok.
> 
> In the initial code, I used WARN() that far more clutters the log (I
> have stated that a backtrace won't provide any useful information, so
> pr_warn() was better suited).
> 
> In add, in my mind, these warnings are debug messages. If they appears,
> the user should probably report a bug.
> 
> Finally, in this patch, I use the same message several times (ok, not
> this particular one). So the function name is a way to differentiate
> them.

You should use dev_*() for these, that way you can properly determine
the exact device as well.

thanks,

greg k-h
diff mbox series

Patch

diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
index b4d5dd3d2d23..8db0be08daf8 100644
--- a/drivers/staging/wfx/data_tx.c
+++ b/drivers/staging/wfx/data_tx.c
@@ -431,7 +431,10 @@  static void wfx_skb_dtor(struct wfx_vif *wvif, struct sk_buff *skb)
 			      sizeof(struct hif_req_tx) +
 			      req->fc_offset;
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		pr_warn("%s: vif associated with the skb does not exist anymore\n", __func__);
+		return;
+	}
 	wfx_tx_policy_put(wvif, req->retry_policy_index);
 	skb_pull(skb, offset);
 	ieee80211_tx_status_irqsafe(wvif->wdev->hw, skb);
diff --git a/drivers/staging/wfx/hif_rx.c b/drivers/staging/wfx/hif_rx.c
index d6dfab094b03..ca09467cba05 100644
--- a/drivers/staging/wfx/hif_rx.c
+++ b/drivers/staging/wfx/hif_rx.c
@@ -110,9 +110,9 @@  static int hif_receive_indication(struct wfx_dev *wdev,
 	const struct hif_ind_rx *body = buf;
 
 	if (!wvif) {
-		dev_warn(wdev->dev, "ignore rx data for non-existent vif %d\n",
-			 hif->interface);
-		return 0;
+		dev_warn(wdev->dev, "%s: ignore rx data for non-existent vif %d\n",
+			 __func__, hif->interface);
+		return -EIO;
 	}
 	skb_pull(skb, sizeof(struct hif_msg) + sizeof(struct hif_ind_rx));
 	wfx_rx_cb(wvif, body, skb);
@@ -128,8 +128,8 @@  static int hif_event_indication(struct wfx_dev *wdev,
 	int type = le32_to_cpu(body->event_id);
 
 	if (!wvif) {
-		dev_warn(wdev->dev, "received event for non-existent vif\n");
-		return 0;
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
 	}
 
 	switch (type) {
@@ -161,7 +161,10 @@  static int hif_pm_mode_complete_indication(struct wfx_dev *wdev,
 {
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
 	complete(&wvif->set_pm_mode_complete);
 
 	return 0;
@@ -173,7 +176,11 @@  static int hif_scan_complete_indication(struct wfx_dev *wdev,
 {
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
+
 	wfx_scan_complete(wvif);
 
 	return 0;
@@ -185,7 +192,10 @@  static int hif_join_complete_indication(struct wfx_dev *wdev,
 {
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
 	dev_warn(wdev->dev, "unattended JoinCompleteInd\n");
 
 	return 0;
@@ -195,11 +205,15 @@  static int hif_suspend_resume_indication(struct wfx_dev *wdev,
 					 const struct hif_msg *hif,
 					 const void *buf)
 {
-	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 	const struct hif_ind_suspend_resume_tx *body = buf;
+	struct wfx_vif *wvif;
 
 	if (body->bc_mc_only) {
-		WARN_ON(!wvif);
+		wvif = wdev_to_wvif(wdev, hif->interface);
+		if (!wvif) {
+			dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+			return -EIO;
+		}
 		if (body->resume)
 			wfx_suspend_resume_mc(wvif, STA_NOTIFY_AWAKE);
 		else
diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
index a246f0d1d6e9..2320a81eae0b 100644
--- a/drivers/staging/wfx/sta.c
+++ b/drivers/staging/wfx/sta.c
@@ -619,6 +619,10 @@  int wfx_set_tim(struct ieee80211_hw *hw, struct ieee80211_sta *sta, bool set)
 	struct wfx_sta_priv *sta_dev = (struct wfx_sta_priv *)&sta->drv_priv;
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, sta_dev->vif_id);
 
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
 	schedule_work(&wvif->update_tim_work);
 	return 0;
 }