Messages in this thread Patch in this message |  | | From | Johan Hovold <> | Subject | [PATCH 1/3] spi: fix use-after-free at controller deregistration | Date | Sun, 29 Oct 2017 12:56:23 +0100 |
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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 <stable@vger.kernel.org> # 4.13 Cc: Suniel Mahesh <sunil.m@techveda.org> Cc: Karthik Tummala <karthik@techveda.org> Signed-off-by: Johan Hovold <johan@kernel.org> --- 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
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