spi: cadence-qspi: fix pointer reference in runtime PM hooks

commit 32ce3bb upstream.

dev_get_drvdata() gets used to acquire the pointer to cqspi and the SPI
controller. Neither embed the other; this lead to memory corruption.

On a given platform (Mobileye EyeQ5) the memory corruption is hidden
inside cqspi->f_pdata. Also, this uninitialised memory is used as a
mutex (ctlr->bus_lock_mutex) by spi_controller_suspend().

Fixes: 2087e85 ("spi: cadence-quadspi: fix suspend-resume implementations")
Reviewed-by: Dhruva Gole <[email protected]>
Signed-off-by: Théo Lebrun <[email protected]>
Link: https://msgid.link/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
Signed-off-by: Zhaoyang Li <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: tleb

drivers/spi/spi-cadence-quadspi.c

@@ -1775,10 +1775,9 @@ static int cqspi_remove(struct platform_device *pdev)
 static int cqspi_suspend(struct device *dev)
 {
 	struct cqspi_st *cqspi = dev_get_drvdata(dev);
-	struct spi_master *master = dev_get_drvdata(dev);
 	int ret;
 
-	ret = spi_master_suspend(master);
+	ret = spi_master_suspend(cqspi->master);
 	cqspi_controller_enable(cqspi, 0);
 
 	clk_disable_unprepare(cqspi->clk);
@@ -1789,7 +1788,6 @@ static int cqspi_suspend(struct device *dev)
 static int cqspi_resume(struct device *dev)
 {
 	struct cqspi_st *cqspi = dev_get_drvdata(dev);
-	struct spi_master *master = dev_get_drvdata(dev);
 
 	clk_prepare_enable(cqspi->clk);
 	cqspi_wait_idle(cqspi);
@@ -1798,7 +1796,7 @@ static int cqspi_resume(struct device *dev)
 	cqspi->current_cs = -1;
 	cqspi->sclk = 0;
 
-	return spi_master_resume(master);
+	return spi_master_resume(cqspi->master);
 }
 
 static DEFINE_SIMPLE_DEV_PM_OPS(cqspi_dev_pm_ops, cqspi_suspend, cqspi_resume);