netdev - Re: [PATCH 3/5] staging: wfx: make warning about pending frame less scary

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Date:   Fri, 13 Mar 2020 15:34:43 +0000
From:   Jérôme Pouiller <Jerome.Pouiller@...abs.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
CC:     "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "David S . Miller" <davem@...emloft.net>,
        Kalle Valo <kvalo@...eaurora.org>
Subject: Re: [PATCH 3/5] staging: wfx: make warning about pending frame less
 scary

On Thursday 12 March 2020 15:30:19 CET Dan Carpenter wrote:
> On Tue, Mar 10, 2020 at 11:13:54AM +0100, Jerome Pouiller wrote:
[...]
> So it really helps me if the commit message restates the subject.  The
> truth is that I don't really even like the advice that Josh wrote in
> the howto about patch descriptions.  I normally start by explaining the
> problem then how I solved it.  But I try not to be a pedant, so long as
> I can understand the problem and the patch that's fine.  So how I would
> write this commit message is:
> 
>     The warning message about releasing a station while Tx is in
>     progress will trigger a stack trace, possibly a reboot depending
>     on the configuration, and a syzbot email.  It's not necessarily
>     a big deal that transmission is still in process so let's make the
>     warning less scary.

Indeed, my idea was the reviewers start by reading subjects and then read
the body of the commit. I will care now.


> > Signed-off-by: Jérôme Pouiller <jerome.pouiller@...abs.com>
> > ---
> >  drivers/staging/wfx/sta.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/wfx/sta.c b/drivers/staging/wfx/sta.c
> > index 03d0f224ffdb..010e13bcd33e 100644
> > --- a/drivers/staging/wfx/sta.c
> > +++ b/drivers/staging/wfx/sta.c
> > @@ -605,7 +605,9 @@ int wfx_sta_remove(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> >       int i;
> >
> >       for (i = 0; i < ARRAY_SIZE(sta_priv->buffered); i++)
> > -             WARN(sta_priv->buffered[i], "release station while Tx is in progress");
> > +             if (sta_priv->buffered[i])
> > +                     dev_warn(wvif->wdev->dev, "release station while %d pending frame on queue %d",
> > +                              sta_priv->buffered[i], i);
> 
> Why print a warning message at all if this is a normal situation?  Just
> delete the whole thing.

I saw cases where it happened and it seems harmless. In add, this code
is going to be released with 5.6. So, the WARN have to be removed.

However, I think it is not normal. Even if it is harmless, it is the
symptom of something unclean.

So, I think that dev_warn() is the correct level of notification.

(I should have included that in the commit log)

-- 
Jérôme Pouiller