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authorJohan Hovold <johan@kernel.org>2017-10-30 13:35:25 +0300
committerMark Brown <broonie@kernel.org>2017-10-31 14:09:23 +0300
commit67f7b2781fafcc0f52464880154b320fea1ae982 (patch)
tree4ecd11b1646048334b8aae7bc2a5acdb9d918b40 /drivers/spi/spi.c
parent2bd6bf03f4c1c59381d62c61d03f6cc3fe71f66e (diff)
downloadlinux-67f7b2781fafcc0f52464880154b320fea1ae982.tar.xz
spi: fix use-after-free at controller deregistration
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@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable <stable@vger.kernel.org>
Diffstat (limited to 'drivers/spi/spi.c')
-rw-r--r--drivers/spi/spi.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6e65524cbfd9..759c9725495a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2240,11 +2240,12 @@ static int __unregister(struct device *dev, void *null)
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,
@@ -2264,7 +2265,7 @@ void spi_unregister_controller(struct spi_controller *ctlr)
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);