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

Normally the last reference on an spi_controller is released by
spi_unregister_controller().  In the case of the i.MX lpspi driver,
the spi_controller is registered with devm_spi_register_controller(),
so spi_unregister_controller() is invoked automatically after the driver
has unbound.

However the driver already releases the last reference in
fsl_lpspi_remove() through a gratuitous call to spi_master_put(),
causing a use-after-free when spi_unregister_controller() is
subsequently invoked by the devres framework.

Fix by dropping the superfluous spi_master_put().

Fixes: 944c01a889 ("spi: lpspi: enable runtime pm for lpspi")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v5.2+
Cc: Han Xu <han.xu@nxp.com>
Link: https://lore.kernel.org/r/ab3c0b18bd820501a12c85e440006e09ec0e275f.1604874488.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lukas Wunner 2020-11-08 23:41:00 +01:00 committed by Mark Brown
parent ee4ad5d065
commit 4def49da62
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1 changed files with 0 additions and 3 deletions
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3
drivers/spi/spi-fsl-lpspi.c
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@ -938,9 +938,6 @@ static int fsl_lpspi_remove(struct platform_device *pdev)
spi_controller_get_devdata(controller);
pm_runtime_disable(fsl_lpspi->dev);
spi_master_put(controller);
return 0;
}