4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold <johan@xxxxxxxxxx>
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 <johan@xxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);