From: Thierry Reding treding@nvidia.com

[ Upstream commit d9a0a05bf8c76e6dc79230669a8b5d685b168c30 ]

Currently when a host1x device driver is unregistered, it is not detached from the host1x controller, which means that the device will stay around and when the driver is registered again, it may bind to the old, stale device rather than the new one that was created from scratch upon driver registration. This in turn can cause various weird crashes within the driver core because it is confronted with a device that was already deleted.

Fix this by detaching the driver from the host1x controller when it is unregistered. This ensures that the deleted device also is no longer present in the device list that drivers will bind to.

Reported-by: Sowjanya Komatineni skomatineni@nvidia.com Signed-off-by: Thierry Reding treding@nvidia.com Tested-by: Sowjanya Komatineni skomatineni@nvidia.com Signed-off-by: Thierry Reding treding@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/host1x/bus.c | 9 +++++++++ 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c index 0121fe7a4548d..02f896b50ed07 100644 --- a/drivers/gpu/host1x/bus.c +++ b/drivers/gpu/host1x/bus.c @@ -632,8 +632,17 @@ EXPORT_SYMBOL(host1x_driver_register_full); */ void host1x_driver_unregister(struct host1x_driver *driver) { + struct host1x *host1x; + driver_unregister(&driver->driver);

+ mutex_lock(&devices_lock); + + list_for_each_entry(host1x, &devices, list) + host1x_detach_driver(host1x, driver); + + mutex_unlock(&devices_lock); + mutex_lock(&drivers_lock); list_del_init(&driver->list); mutex_unlock(&drivers_lock);