spi: bcm2835: Fix use-after-free on unbind

[ Upstream commit e1483ac030fb4c57734289742f1c1d38dca61e22 ]

bcm2835_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() helper which
keeps the private data accessible until the driver has unbound.

Fixes: f8043872e796 ("spi: add driver for BCM2835")
Reported-by: Sascha Hauer <s.hauer@pengutronix.de>
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v3.10+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v3.10+
Cc: Vladimir Oltean <olteanv@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/ad66e0a0ad96feb848814842ecf5b6a4539ef35c.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index df6abc75bc1679a6220f1e016f50c9d343d08a7d..2908df35466f02d7926e741ec1c5043b8d90680a 100644 (file)
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -737,7 +737,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
        struct resource *res;
        int err;
 
-       master = spi_alloc_master(&pdev->dev, sizeof(*bs));
+       master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs));
        if (!master) {
                dev_err(&pdev->dev, "spi_alloc_master() failed\n");
                return -ENOMEM;
@@ -759,23 +759,20 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        bs->regs = devm_ioremap_resource(&pdev->dev, res);
-       if (IS_ERR(bs->regs)) {
-               err = PTR_ERR(bs->regs);
-               goto out_master_put;
-       }
+       if (IS_ERR(bs->regs))
+               return PTR_ERR(bs->regs);
 
        bs->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(bs->clk)) {
                err = PTR_ERR(bs->clk);
                dev_err(&pdev->dev, "could not get clk: %d\n", err);
-               goto out_master_put;
+               return err;
        }
 
        bs->irq = platform_get_irq(pdev, 0);
        if (bs->irq <= 0) {
                dev_err(&pdev->dev, "could not get IRQ: %d\n", bs->irq);
-               err = bs->irq ? bs->irq : -ENODEV;
-               goto out_master_put;
+               return bs->irq ? bs->irq : -ENODEV;
        }
 
        clk_prepare_enable(bs->clk);
@@ -803,8 +800,6 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 
 out_clk_disable:
        clk_disable_unprepare(bs->clk);
-out_master_put:
-       spi_master_put(master);
        return err;
 }