Commit 1e7cbfaa authored by Rishabh Bhatnagar's avatar Rishabh Bhatnagar Committed by Sudeep Holla
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firmware: arm_scmi: Free mailbox channels if probe fails 

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.

    | arm-scmi soc:qcom,scmi: timed out in resp(caller: version_get+0x84/0x140)
    | arm-scmi soc:qcom,scmi: unable to communicate with SCMI
    | 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.

     | rx_callback+0x24/0x160
     | mbox_chan_received_data+0x44/0x94
     | __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.

Link: https://lore.kernel.org/r/1628111999-21595-1-git-send-email-rishabhb@codeaurora.org


Tested-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Reviewed-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Signed-off-by: default avatarRishabh Bhatnagar <rishabhb@codeaurora.org>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 46abe13b

drivers/firmware/arm_scmi/driver.c

+24 −11
Original line number Diff line number Diff line
@@ -1787,6 +1787,21 @@ void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table) 
	mutex_unlock(&scmi_requested_devices_mtx);

}



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;
@@ -1833,7 +1848,7 @@ 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");
@@ -1846,7 +1861,7 @@ 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);
@@ -1885,6 +1900,12 @@ 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)
@@ -1896,7 +1917,6 @@ 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);
@@ -1920,14 +1940,7 @@ 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);

}



static ssize_t protocol_version_show(struct device *dev,