Re: [PATCH] firmware: arm_scmi: Free mailbox channels if probe fails
From: Cristian Marussi <cristian.marussi@arm.com>
Date: 2021-08-04 08:34:07
On Tue, Aug 03, 2021 at 03:22:22PM -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. Change-Id: I1214ec2c4c92c4a3ca5fa73de11e0e403b13b46a Signed-off-by: Rishabh Bhatnagar <redacted>
Hi Rishabh, Good catch, thanks for this.
quoted hunk
--- drivers/firmware/arm_scmi/driver.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 9b2e8d4..518c7b9 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c@@ -1430,7 +1430,7 @@ 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 +1443,7 @@ 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 +1482,13 @@ static int scmi_probe(struct platform_device *pdev) } return 0; + +notification_exit: + scmi_notification_exit(&info->handle); +clear_txrx_setup: + idr_for_each(&info->tx_idr, info->desc->ops->chan_free, &info->tx_idr); + idr_for_each(&info->rx_idr, info->desc->ops->chan_free, &info->rx_idr); + return ret; }
Shouldn't we also clear the internal IDRs memory allocs after these idr_for_each() adding a couple of: idr_destroy(&info->tx_idr); idr_destroy(&info->rx_idr); like scmi_remove() does ? Thanks, Cristian _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel