Messages in this thread | | | Date | Thu, 5 Aug 2021 11:54:27 +0100 | From | Cristian Marussi <> | Subject | Re: [PATCH v3] firmware: arm_scmi: Free mailbox channels if probe fails |
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On Wed, Aug 04, 2021 at 02:19:59PM -0700, Rishabh Bhatnagar wrote: > Mailbox channels for the base protocol are setup during probe. > There can be a scenario where probe fails to acquire the base > protocol due to a timeout leading to cleaning up of all device > managed memory including the scmi_mailbox structure setup during > mailbox_chan_setup function. > [ 12.735104]arm-scmi soc:qcom,scmi: timed out in resp(caller: version_get+0x84/0x140) > [ 12.735224]arm-scmi soc:qcom,scmi: unable to communicate with SCMI > [ 12.735947]arm-scmi: probe of soc:qcom,scmi failed with error -110 > > Now when a message arrives at cpu slightly after the timeout, the mailbox > controller will try to call the rx_callback of the client and might end > up accessing freed memory. > [ 12.758363][ C0] Call trace: > [ 12.758367][ C0] rx_callback+0x24/0x160 > [ 12.758372][ C0] mbox_chan_received_data+0x44/0x94 > [ 12.758386][ C0] __handle_irq_event_percpu+0xd4/0x240 > This patch frees the mailbox channels setup during probe and adds some more > error handling in case the probe fails. > > Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org> > --- > drivers/firmware/arm_scmi/driver.c | 35 ++++++++++++++++++++++++----------- > 1 file changed, 24 insertions(+), 11 deletions(-) > > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c > index 9b2e8d4..ead3bd3 100644 > --- a/drivers/firmware/arm_scmi/driver.c > +++ b/drivers/firmware/arm_scmi/driver.c > @@ -1390,6 +1390,21 @@ void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table) > mutex_unlock(&scmi_requested_devices_mtx); > } >
Hi,
> +static int scmi_cleanup_txrx_channels(struct scmi_info *info) > +{ > + int ret; > + struct idr *idr = &info->tx_idr; > + > + ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > + idr_destroy(&info->tx_idr); > + > + idr = &info->rx_idr; > + ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > + idr_destroy(&info->rx_idr); > + > + return ret; > +} > + > static int scmi_probe(struct platform_device *pdev) > { > int ret; > @@ -1430,7 +1445,7 @@ static int scmi_probe(struct platform_device *pdev) > > ret = scmi_xfer_info_init(info); > if (ret) > - return ret; > + goto clear_txrx_setup; > > if (scmi_notification_init(handle)) > dev_err(dev, "SCMI Notifications NOT available.\n"); > @@ -1443,7 +1458,7 @@ static int scmi_probe(struct platform_device *pdev) > ret = scmi_protocol_acquire(handle, SCMI_PROTOCOL_BASE); > if (ret) { > dev_err(dev, "unable to communicate with SCMI\n"); > - return ret; > + goto notification_exit; > } > > mutex_lock(&scmi_list_mutex); > @@ -1482,6 +1497,12 @@ static int scmi_probe(struct platform_device *pdev) > } > > return 0; > + > +notification_exit: > + scmi_notification_exit(&info->handle); > +clear_txrx_setup: > + scmi_cleanup_txrx_channels(info); > + return ret; > } > > void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id) > @@ -1493,7 +1514,6 @@ static int scmi_remove(struct platform_device *pdev) > { > int ret = 0, id; > struct scmi_info *info = platform_get_drvdata(pdev); > - struct idr *idr = &info->tx_idr; > struct device_node *child; > > mutex_lock(&scmi_list_mutex); > @@ -1517,14 +1537,7 @@ static int scmi_remove(struct platform_device *pdev) > idr_destroy(&info->active_protocols); > > /* Safe to free channels since no more users */ > - ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > - idr_destroy(&info->tx_idr); > - > - idr = &info->rx_idr; > - ret = idr_for_each(idr, info->desc->ops->chan_free, idr); > - idr_destroy(&info->rx_idr); > - > - return ret; > + return scmi_cleanup_txrx_channels(info); > } >
Looks good to me.
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com> Tested-by: Cristian Marussi <cristian.marussi@arm.com> (Re-tested on for-next/scmi on top of virtio-scmi series)
Thanks, Cristian
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