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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: 9b61e30221
("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>
This commit is contained in:
parent
2bd6bf03f4
commit
67f7b2781f
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@ -2240,11 +2240,12 @@ static int __unregister(struct device *dev, void *null)
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void spi_unregister_controller(struct spi_controller *ctlr)
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void spi_unregister_controller(struct spi_controller *ctlr)
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{
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{
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struct spi_controller *found;
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struct spi_controller *found;
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int id = ctlr->bus_num;
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int dummy;
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int dummy;
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/* First make sure that this controller was ever added */
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/* First make sure that this controller was ever added */
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mutex_lock(&board_lock);
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mutex_lock(&board_lock);
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found = idr_find(&spi_master_idr, ctlr->bus_num);
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found = idr_find(&spi_master_idr, id);
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mutex_unlock(&board_lock);
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mutex_unlock(&board_lock);
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if (found != ctlr) {
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if (found != ctlr) {
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dev_dbg(&ctlr->dev,
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dev_dbg(&ctlr->dev,
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@ -2264,7 +2265,7 @@ void spi_unregister_controller(struct spi_controller *ctlr)
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device_unregister(&ctlr->dev);
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device_unregister(&ctlr->dev);
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/* free bus id */
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/* free bus id */
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mutex_lock(&board_lock);
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mutex_lock(&board_lock);
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idr_remove(&spi_master_idr, ctlr->bus_num);
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idr_remove(&spi_master_idr, id);
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mutex_unlock(&board_lock);
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mutex_unlock(&board_lock);
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}
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}
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EXPORT_SYMBOL_GPL(spi_unregister_controller);
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EXPORT_SYMBOL_GPL(spi_unregister_controller);
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