usb: gadget: tegra-xudc: Fix possible use-after-free in tegra_xudc_remove()

BugLink: https://bugs.launchpad.net/bugs/1928857
[ Upstream commit a932ee40c276767cd55fadec9e38829bf441db41 ]

This driver's remove path calls cancel_delayed_work(). However, that
function does not wait until the work function finishes. This means
that the callback function may still be running after the driver's
remove function has finished, which would result in a use-after-free.

Fix by calling cancel_delayed_work_sync(), which ensures that
the work is properly cancelled, no longer running, and unable
to re-schedule itself.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20210407092947.3271507-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/tegra-xudc.c
index 580bef8eb4cbcc5403c7a5660b33eccf1772da74..2319c9737c2bd3d220b0b857a38b4282a8c96d14 100644 (file)
--- a/drivers/usb/gadget/udc/tegra-xudc.c
+++ b/drivers/usb/gadget/udc/tegra-xudc.c
@@ -3883,7 +3883,7 @@ static int tegra_xudc_remove(struct platform_device *pdev)
 
        pm_runtime_get_sync(xudc->dev);
 
-       cancel_delayed_work(&xudc->plc_reset_work);
+       cancel_delayed_work_sync(&xudc->plc_reset_work);
        cancel_work_sync(&xudc->usb_role_sw_work);
 
        usb_del_gadget_udc(&xudc->gadget);