The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5626308bb94d9f930aa5f7c77327df4c6daa7759 Mon Sep 17 00:00:00 2001
From: Lukas Wunner lukas@wunner.de Date: Mon, 7 Dec 2020 09:17:05 +0100 Subject: [PATCH] spi: pxa2xx: Fix use-after-free on unbind
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/5764b04d4a6e43069ebb7808f64c2f774ac6f193.160728688... Signed-off-by: Mark Brown broonie@kernel.org
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index 62a0f0f86553..bd2354fd438d 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -1691,9 +1691,9 @@ static int pxa2xx_spi_probe(struct platform_device *pdev) }
if (platform_info->is_slave) - controller = spi_alloc_slave(dev, sizeof(struct driver_data)); + controller = devm_spi_alloc_slave(dev, sizeof(*drv_data)); else - controller = spi_alloc_master(dev, sizeof(struct driver_data)); + controller = devm_spi_alloc_master(dev, sizeof(*drv_data));
if (!controller) { dev_err(&pdev->dev, "cannot alloc spi_controller\n"); @@ -1916,7 +1916,6 @@ static int pxa2xx_spi_probe(struct platform_device *pdev) free_irq(ssp->irq, drv_data);
out_error_controller_alloc: - spi_controller_put(controller); pxa_ssp_free(ssp); return status; }