Re: [PATCH v1 RESEND] slimbus: stream: Add null pointer check for client functions

[Viken Dadhaniya <quic_vdadhani@xxxxxxxxxxx>]

On 4/11/2024 3:19 PM, Srinivas Kandagatla wrote:
> Thanks Viken for the patch,
>
> On 27/03/2024 08:32, Viken Dadhaniya wrote:
> > There is a possible scenario where client driver is calling
> > slimbus stream APIs in incorrect sequence and it might lead to
> > invalid null access of the stream pointer in slimbus
> > enable/disable/prepare/unprepare/free function.
> >
> > Fix this by checking validity of the stream before accessing in
> > all function API’s exposed to client.
> >
> > Signed-off-by: Viken Dadhaniya <quic_vdadhani@xxxxxxxxxxx>
> > ---
> >   drivers/slimbus/stream.c | 37 +++++++++++++++++++++++++++++++++----
> >   1 file changed, 33 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/slimbus/stream.c b/drivers/slimbus/stream.c
> > index 1d6b38657917..c5a436fd0952 100644
> > --- a/drivers/slimbus/stream.c
> > +++ b/drivers/slimbus/stream.c
> > @@ -202,10 +202,16 @@ static int slim_get_prate_code(int rate)
> >   int slim_stream_prepare(struct slim_stream_runtime *rt,
> >               struct slim_stream_config *cfg)
> >   {
> > -    struct slim_controller *ctrl = rt->dev->ctrl;
> > +    struct slim_controller *ctrl;
> >       struct slim_port *port;
> >       int num_ports, i, port_id, prrate;
> > +    if (!rt || !cfg) {
> > +        pr_err("%s: Stream or cfg is NULL, Check from client side\n", 
> > __func__);
>
> Please use dev_err where possible
>
>
> --srini


For error scenario, we don't have valid dev to be used in dev_err 
argument. this log will help for debug.
Please let us know if any concern with pr_err.


> > +        return -EINVAL;
> > +    }
> > +
> > +    ctrl = rt->dev->ctrl;
> >       if (rt->ports) {
> >           dev_err(&rt->dev->dev, "Stream already Prepared\n");
> >           return -EINVAL;
> > @@ -358,9 +364,15 @@ int slim_stream_enable(struct slim_stream_runtime 
> > *stream)
> >   {
> >       DEFINE_SLIM_BCAST_TXN(txn, SLIM_MSG_MC_BEGIN_RECONFIGURATION,
> >                   3, SLIM_LA_MANAGER, NULL);
> > -    struct slim_controller *ctrl = stream->dev->ctrl;
> > +    struct slim_controller *ctrl;
> >       int ret, i;
> > +    if (!stream) {
> > +        pr_err("%s: Stream is NULL, Check from client side\n", 
> > __func__);
> > +        return -EINVAL;
> > +    }
> > +
> > +    ctrl = stream->dev->ctrl;
> >       if (ctrl->enable_stream) {
> >           ret = ctrl->enable_stream(stream);
> >           if (ret)
> > @@ -411,12 +423,18 @@ int slim_stream_disable(struct 
> > slim_stream_runtime *stream)
> >   {
> >       DEFINE_SLIM_BCAST_TXN(txn, SLIM_MSG_MC_BEGIN_RECONFIGURATION,
> >                   3, SLIM_LA_MANAGER, NULL);
> > -    struct slim_controller *ctrl = stream->dev->ctrl;
> > +    struct slim_controller *ctrl;
> >       int ret, i;
> > +    if (!stream) {
> > +        pr_err("%s: Stream is NULL, Check from client side\n", 
> > __func__);
> > +        return -EINVAL;
> > +    }
> > +
> >       if (!stream->ports || !stream->num_ports)
> >           return -EINVAL;
> > +    ctrl = stream->dev->ctrl;
> >       if (ctrl->disable_stream)
> >           ctrl->disable_stream(stream);
> > @@ -448,6 +466,11 @@ int slim_stream_unprepare(struct 
> > slim_stream_runtime *stream)
> >   {
> >       int i;
> > +    if (!stream) {
> > +        pr_err("%s: Stream is NULL, Check from client side\n", 
> > __func__);
> > +        return -EINVAL;
> > +    }
> > +
> >       if (!stream->ports || !stream->num_ports)
> >           return -EINVAL;
> > @@ -476,8 +499,14 @@ EXPORT_SYMBOL_GPL(slim_stream_unprepare);
> >    */
> >   int slim_stream_free(struct slim_stream_runtime *stream)
> >   {
> > -    struct slim_device *sdev = stream->dev;
> > +    struct slim_device *sdev;
> > +
> > +    if (!stream) {
> > +        pr_err("%s: Stream is NULL, Check from client side\n", 
> > __func__);
> > +        return -EINVAL;
> > +    }
> > +    sdev = stream->dev;
> >       spin_lock(&sdev->stream_list_lock);
> >       list_del(&stream->node);
> >       spin_unlock(&sdev->stream_list_lock);