[PATCH 4.9 13/25] spi: pxa2xx: Fix use-after-free on unbind

Greg Kroah-Hartman
2021-01-15T13:08:09Z

From: Lukas Wunner <lukas@wunner.de>

commit 5626308bb94d9f930aa5f7c77327df4c6daa7759 upstream

pxa2xx_spi_remove() accesses the driver's private data after calling
spi_unregister_controller() even though that function releases the last
reference on the spi_controller and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master/slave() helper
which keeps the private data accessible until the driver has unbound.

Fixes: 32e5b57232c0 ("spi: pxa2xx: Fix controller unregister order")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v2.6.17+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v2.6.17+: 32e5b57232c0: spi: pxa2xx: Fix controller unregister order
Cc: <stable@vger.kernel.org> # v2.6.17+
Link: https://lore.kernel.org/r/5764b04d4a6e43069ebb7808f64c2f774ac6f193.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/spi/spi-pxa2xx.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -1606,7 +1606,7 @@ static int pxa2xx_spi_probe(struct platf
return -ENODEV;
}

- master = spi_alloc_master(dev, sizeof(struct driver_data));
+ master = devm_spi_alloc_master(dev, sizeof(*drv_data));
if (!master) {
dev_err(&pdev->dev, "cannot alloc spi_master\n");
pxa_ssp_free(ssp);
@@ -1788,7 +1788,6 @@ out_error_clock_enabled:
free_irq(ssp->irq, drv_data);

out_error_master_alloc:
- spi_master_put(master);
pxa_ssp_free(ssp);
return status;
}