On 3/16/23 12:09, Zheng Wang wrote:
In vudc_probe, it calls init_vudc_hw, which bound &udc->timer with v_timer.
When it calls usbip_sockfd_store, it will call v_start_timer to start the
timer work.
When we call vudc_remove to remove the driver, theremay be a sequence as
follows:
Fix it by shutdown the timer work before cleanup in vudc_remove.
Note that removing a driver is a root-only operation, and should never
happen.
CPU0 CPU1
|v_timer
vudc_remove |
kfree(udc); |
//free shost |
|udc->gadget
|//use
This bug was found by static analysis.
Tell me which static analysis tool did you use to find this and
the output from the tool.
Fixes: b6a0ca111867 ("usbip: vudc: Add UDC specific ops")
Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
---
v2:
- add more details about how the bug was found suggested by Shuah
---
drivers/usb/usbip/vudc_dev.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c
index 2bc428f2e261..33d0991755bb 100644
--- a/drivers/usb/usbip/vudc_dev.c
+++ b/drivers/usb/usbip/vudc_dev.c
@@ -633,6 +633,7 @@ int vudc_remove(struct platform_device *pdev)
{
struct vudc *udc = platform_get_drvdata(pdev);
+ timer_shutdown_sync(&udc->timer);
usb_del_gadget_udc(&udc->gadget);
cleanup_vudc_hw(udc);
kfree(udc);
thanks,
-- Shuah
