4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Johan Hovold <[email protected]> commit 67f7b2781fafcc0f52464880154b320fea1ae982 upstream. The controller is typically freed as part of device_unregister() so store the bus id before deregistration to avoid use-after-free when the id is later released. Fixes: 9b61e302210e ("spi: Pick spi bus number from Linux idr or spi alias") Signed-off-by: Johan Hovold <[email protected]> Signed-off-by: Mark Brown <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/spi/spi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2245,11 +2245,12 @@ static int __unregister(struct device *d void spi_unregister_controller(struct spi_controller *ctlr) { struct spi_controller *found; + int id = ctlr->bus_num; int dummy; /* First make sure that this controller was ever added */ mutex_lock(&board_lock); - found = idr_find(&spi_master_idr, ctlr->bus_num); + found = idr_find(&spi_master_idr, id); mutex_unlock(&board_lock); if (found != ctlr) { dev_dbg(&ctlr->dev, @@ -2269,7 +2270,7 @@ void spi_unregister_controller(struct sp device_unregister(&ctlr->dev); /* free bus id */ mutex_lock(&board_lock); - idr_remove(&spi_master_idr, ctlr->bus_num); + idr_remove(&spi_master_idr, id); mutex_unlock(&board_lock); } EXPORT_SYMBOL_GPL(spi_unregister_controller);
