On Thu, Feb 06, 2020 at 12:18:27PM -0800, Bjorn Andersson wrote:
> On Wed 05 Feb 21:54 PST 2020, Nikita Shubin wrote:
>
> > .kick method not set in rproc_ops will result in:
> >
> > 8<--- cut here ---
> > Unable to handle kernel NULL pointer dereference
> >
> > in rproc_virtio_notify, after firmware loading.
> >
> > At least a warning needed on attempt to call missing method.
>
> Is this not a fatal error only happening during development? In which
> case the NULL pointer dereference will come with an oops with sufficient
> information to pinpoint what's going on?
Hello, Bjorn.
This error is happenning if no kick method was defined for struct
rproc_ops, like, for example, in imx_rproc.
Looks, like if we have a resource table with defined vring's in it, a
virtqueue will be allocated in rp_find_vq, passing rproc_virtio_notify.
But may be it's a better way to refuse calling vring_new_virtqueue if kick
method method is not defined. To avoid explicit load in rproc_virtio_notify.
>
> Regards,
> Bjorn
>
> >
> > Signed-off-by: Nikita Shubin <NShubin@xxxxxxxxxx>
> > ---
> > drivers/remoteproc/remoteproc_virtio.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
> > index 8c07cb2ca8ba..77a81f331e3f 100644
> > --- a/drivers/remoteproc/remoteproc_virtio.c
> > +++ b/drivers/remoteproc/remoteproc_virtio.c
> > @@ -32,6 +32,12 @@ static bool rproc_virtio_notify(struct virtqueue *vq)
> >
> > dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);
> >
> > + if (unlikely(rproc->ops->kick == NULL)) {
> > + WARN_ONCE(rproc->ops->kick == NULL, ".kick method not defined for %s",
> > + rproc->name);
> > + return false;
> > + }
> > +
> > rproc->ops->kick(rproc, notifyid);
> > return true;
> > }
> > --
> > 2.24.1
> >
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