Messages in this thread | | | From | Jett ✈ Rink <> | Date | Thu, 4 Apr 2019 10:00:00 -0600 | Subject | Re: [PATCH v2] mfd: cros_ec: check for NULL transfer function |
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Reviewed-by: Jett Rink <jettrink@chromium.org>
On Wed, Apr 3, 2019 at 4:40 PM <egranata@chromium.org> wrote: > > From: Enrico Granata <egranata@chromium.org> > > As new transfer mechanisms are added to the EC codebase, they may > not support v2 of the EC protocol. > > If the v3 initial handshake transfer fails, the kernel will try > and call cmd_xfer as a fallback. If v2 is not supported, cmd_xfer > will be NULL, and the code will end up causing a kernel panic. > > Add a check for NULL before calling the transfer function, along > with a helpful comment explaining how one might end up in this > situation. > > Signed-off-by: Enrico Granata <egranata@chromium.org> > --- > drivers/platform/chrome/cros_ec_proto.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c > index 97a068dff192d..55691656a3c27 100644 > --- a/drivers/platform/chrome/cros_ec_proto.c > +++ b/drivers/platform/chrome/cros_ec_proto.c > @@ -56,6 +56,16 @@ static int send_command(struct cros_ec_device *ec_dev, > else > xfer_fxn = ec_dev->cmd_xfer; > > + if (xfer_fxn == NULL) { > + /* This error can happen if a communication error happened and > + * the EC is trying to use protocol v2, on an underlying > + * communication mechanism that does not support v2. > + */ > + dev_err_once(ec_dev->dev, > + "missing EC transfer API, cannot send command\n"); > + return -EIO; > + } > + > ret = (*xfer_fxn)(ec_dev, msg); > if (msg->result == EC_RES_IN_PROGRESS) { > int i; > -- > 2.21.0.392.gf8f6787159e-goog >
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