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spi: bcm2835aux: Fix use-after-free on unbind 

bcm2835aux_spi_remove() accesses the driver's private data after calling
spi_unregister_master() even though that function releases the last
reference on the spi_master 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: b9dd3f6d41 ("spi: bcm2835aux: Fix controller unregister order")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v4.4+: 123456789abc: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v4.4+: b9dd3f6d4172: spi: bcm2835aux: Fix controller unregister order
Cc: <stable@vger.kernel.org> # v4.4+
Link: https://lore.kernel.org/r/b290b06357d0c0bdee9cecc539b840a90630f101.1605121038.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
zero-sugar-mainline-defconfig
Lukas Wunner 2020-11-11 20:07:30 +01:00 committed by Mark Brown
parent e1483ac030
commit e13ee6cc47
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GPG Key ID: 24D68B725D5487D0
1 changed files with 7 additions and 14 deletions
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21
drivers/spi/spi-bcm2835aux.c
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@ -494,7 +494,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
unsigned long clk_hz;
int err;
master = spi_alloc_master(&pdev->dev, sizeof(*bs));
master = devm_spi_alloc_master(&pdev->dev, sizeof(*bs));
if (!master)
return -ENOMEM;
@ -524,29 +524,24 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
/* the main area */
bs->regs = devm_platform_ioremap_resource(pdev, 0);
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 PTR_ERR(bs->clk);
}
bs->irq = platform_get_irq(pdev, 0);
if (bs->irq <= 0) {
err = bs->irq ? bs->irq : -ENODEV;
goto out_master_put;
}
if (bs->irq <= 0)
return bs->irq ? bs->irq : -ENODEV;
/* this also enables the HW block */
err = clk_prepare_enable(bs->clk);
if (err) {
dev_err(&pdev->dev, "could not prepare clock: %d\n", err);
goto out_master_put;
return err;
}
/* just checking if the clock returns a sane value */
@ -581,8 +576,6 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev)
out_clk_disable:
clk_disable_unprepare(bs->clk);
out_master_put:
spi_master_put(master);
return err;
}