Re: [PATCH] comedi: drivers: pcl730: Fix potential memory leak in pcl730_attach()

[shangxiaojing]

On 2022/11/22 20:18, Ian Abbott wrote:
> On 22/11/2022 12:04, Shang XiaoJing wrote:
> > pcl730_attach() calls comedi_request_region() and won't release the
> > resource allocated by alloc_resource() when pcl730_attach() failed 
> > latter.
> > Add release_region() to prevent memory leak.
> >
> > Fixes: 6f9aa29b47f6 ("staging: comedi: pcl730: use 
> > comedi_request_region()")
> > Signed-off-by: Shang XiaoJing <shangxiaojing@xxxxxxxxxx>
> > ---
> >   drivers/comedi/drivers/pcl730.c | 8 +++++++-
> >   1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/comedi/drivers/pcl730.c 
> > b/drivers/comedi/drivers/pcl730.c
> > index d2733cd5383d..c463de8a14e1 100644
> > --- a/drivers/comedi/drivers/pcl730.c
> > +++ b/drivers/comedi/drivers/pcl730.c
> > @@ -274,8 +274,14 @@ static int pcl730_attach(struct comedi_device *dev,
> >           return ret;
> >       ret = comedi_alloc_subdevices(dev, board->n_subdevs);
> > -    if (ret)
> > +    if (ret) {
> > +        if (dev->iobase && dev->iolen) {
> > +            release_region(dev->iobase, dev->iolen);
> > +            dev->iobase = 0;
> > +            dev->iolen = 0;
> > +        }
> >           return ret;
> > +    }
> >       subdev = 0;
>
> This is not needed.  If the 'attach' handler pcl730_attach() returns an 
> error, the 'detach' handler comedi_legacy_detach() will be called to 
> clean up the allocated resources.  All the comedi drivers work that way. 
> (A lot of them have an 'auto_attach' handler instead of an 'attach' 
> handler, but the error handling is basically the same.)

ok, thanks for the advice!

Thanks,
--
Shang XiaoJing