This bug exists in drivers/usb/cdns3/cdns3-gadget.c. Function
__cdns3_gadget_init will call cdns3_gadget_start to do futher jobs
during the initialization proccess of cdns3 gadget. In cdns3_gadget_start,
&priv_dev->pending_status_wq is bound with cdns3_pending_setup_status_handler.
Then this work will be added to system_freezable_wq in cdns3_gadget_ep0_queue.
Here is the code.
queue_work(system_freezable_wq, &priv_dev->pending_status_wq);
If we call cdns3_gadget_exit to remove the device and make cleanup,
there are some unfinished works. This function will call cdns3_free_all_eps to
free all the endpoints. However, if cdns3_pending_setup_status_handler is
scheduled to run after the free job, it will cause use-after-free error as
cdns3_pending_setup_status_handler will use the endpoint in the following code.
request->complete(&priv_dev->eps[0]->endpoint, request);
The possible execution flow that may lead to this issue is as follows:
CPU0 CPU1
| __cdns3_gadget_init
| cdns3_gadget_start
cdns3_gadget_exit |
cdns3_free_all_eps |
devm_kfree (free) |
| cdns3_pending_setup_status_handler
| &priv_dev->eps[0]->endpoint (use)
Fix it by cleaning the work in cdns3_gadget_exit.
Signed-off-by: Sicong Huang <congei42@xxxxxxx>
---
drivers/usb/cdns3/cdns3-gadget.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index fd1beb10bba7..0f2e143bd17a 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -3252,6 +3252,9 @@ static void cdns3_gadget_exit(struct cdns *cdns)
pm_runtime_mark_last_busy(cdns->dev);
pm_runtime_put_autosuspend(cdns->dev);
+ cancel_work_sync(&priv_dev->pending_status_wq);
+ cancel_work_sync(&priv_dev->aligned_buf_wq);
+
usb_del_gadget(&priv_dev->gadget);
devm_free_irq(cdns->dev, cdns->dev_irq, priv_dev);
--
2.34.1
