The delayed work item otg_event is initialized in fsl_otg_conf() and
scheduled under two conditions:
1. When a host controller binds to the OTG controller.
2. When the USB ID pin state changes (cable insertion/removal).
A race condition occurs when the device is removed via fsl_otg_remove():
the fsl_otg instance may be freed while the delayed work is still pending
or executing. This leads to use-after-free when the work function
fsl_otg_event() accesses the already freed memory.
The problematic scenario:
(detach thread) | (delayed work)
fsl_otg_remove() |
kfree(fsl_otg_dev) //FREE| fsl_otg_event()
| og = container_of(...) //USE
| og-> //USE
Fix this by calling disable_delayed_work_sync() in fsl_otg_remove()
before deallocating the fsl_otg structure. This ensures the delayed work
is properly canceled and completes execution prior to memory deallocation.
This bug was identified through static analysis.
Fixes: 0807c500a1a6 ("USB: add Freescale USB OTG Transceiver driver")
Cc: [email protected]
Signed-off-by: Duoming Zhou <[email protected]>
---
drivers/usb/phy/phy-fsl-usb.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/usb/phy/phy-fsl-usb.c b/drivers/usb/phy/phy-fsl-usb.c
index 40ac68e52ce..e266a47c4d4 100644
--- a/drivers/usb/phy/phy-fsl-usb.c
+++ b/drivers/usb/phy/phy-fsl-usb.c
@@ -988,6 +988,7 @@ static void fsl_otg_remove(struct platform_device *pdev)
{
struct fsl_usb2_platform_data *pdata = dev_get_platdata(&pdev->dev);
+ disable_delayed_work_sync(&fsl_otg_dev->otg_event);
usb_remove_phy(&fsl_otg_dev->phy);
free_irq(fsl_otg_dev->irq, fsl_otg_dev);
--
2.34.1
