Date:   Mon, 27 Feb 2023 10:18:14 +0300
From:   Dan Carpenter <error27@gmail.com>
To:     Kang Chen <void0red@gmail.com>
Cc:     paskripkin@gmail.com, Larry.Finger@lwfinger.net,
        phil@philpotter.co.uk, gregkh@linuxfoundation.org,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: r8188eu: add a null check of kzalloc in
 go_add_group_info_attr
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References: <20230226132500.3933232-1-void0red@gmail.com>
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On Mon, Feb 27, 2023 at 03:11:21PM +0800, Kang Chen wrote:
> Hi, Dan,
> 
> Thanks for your review.
> I noticed there is no error handling in the origin design (this call chain).
> go_add_group_info_attr returns a len-like value indicating the length
> of pbuf.
> I don't think throwing an error to the caller is a good idea, the caller
> doesn't seem to care about it.
> So inserting a netdev_dbg or pr_debug here might be enough.
> Do you have a better idea?

As I mentioned in my email, we need to fix the caller to care about it.

regards,
dan carpenter

> 
> Best regards,
> Kang Chen
> 
> 
> On Mon, Feb 27, 2023 at 12:47 PM Dan Carpenter <error27@gmail.com> wrote:
> >
> > On Sun, Feb 26, 2023 at 09:25:00PM +0800, Kang Chen wrote:
> > > kzalloc may fails, pdata_attr might be null and will cause
> > > illegal address access later.
> > >
> > > Signed-off-by: Kang Chen <void0red@gmail.com>
> > > ---
> > >  drivers/staging/r8188eu/core/rtw_p2p.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/staging/r8188eu/core/rtw_p2p.c b/drivers/staging/r8188eu/core/rtw_p2p.c
> > > index 93d3c9c43..802e1170a 100644
> > > --- a/drivers/staging/r8188eu/core/rtw_p2p.c
> > > +++ b/drivers/staging/r8188eu/core/rtw_p2p.c
> > > @@ -31,6 +31,8 @@ static u32 go_add_group_info_attr(struct wifidirect_info *pwdinfo, u8 *pbuf)
> > >       struct sta_priv *pstapriv = &padapter->stapriv;
> > >
> > >       pdata_attr = kzalloc(MAX_P2P_IE_LEN, GFP_KERNEL);
> > > +     if (!pdata_attr)
> > > +             return 0;
> >
> > Return success here is not a good thing.  We have to fix the caller to
> > check for errors.  (Fixing a bug half way just makes it harder to find
> > the bug so it makes the situation worse).
> >
> > regards,
> > dan carpenter
> >