From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Subject: [PATCH v2 1/3] spi: fix use-after-free at controller deregistration Date: Mon, 30 Oct 2017 11:35:25 +0100 Message-ID: <20171030103527.13535-1-johan@kernel.org> Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Lars-Peter Clausen , Johan Hovold , stable , Suniel Mahesh , Karthik Tummala To: Mark Brown Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org 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") Cc: stable # 4.13 Cc: Suniel Mahesh Cc: Karthik Tummala Signed-off-by: Johan Hovold --- drivers/spi/spi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index e8b5a5e21b2e..3ff0ee88c467 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2245,11 +2245,12 @@ 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, @@ -2269,7 +2270,7 @@ 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); -- 2.14.3