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From: =?utf-8?q?Th=C3=A9o_Lebrun?= <theo.lebrun@bootlin.com>
Date: Thu, 22 Feb 2024 11:12:29 +0100
Subject: [PATCH v4 1/4] spi: cadence-qspi: fix pointer reference in runtime
 PM hooks
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Message-Id: <20240222-cdns-qspi-pm-fix-v4-1-6b6af8bcbf59@bootlin.com>
References: <20240222-cdns-qspi-pm-fix-v4-0-6b6af8bcbf59@bootlin.com>
In-Reply-To: <20240222-cdns-qspi-pm-fix-v4-0-6b6af8bcbf59@bootlin.com>
To: Mark Brown <broonie@kernel.org>, Apurva Nandan <a-nandan@ti.com>, 
 Dhruva Gole <d-gole@ti.com>
Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, 
 Gregory CLEMENT <gregory.clement@bootlin.com>, 
 Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>, 
 Thomas Petazzoni <thomas.petazzoni@bootlin.com>, 
 Tawfik Bayouk <tawfik.bayouk@mobileye.com>, 
 =?utf-8?q?Th=C3=A9o_Lebrun?= <theo.lebrun@bootlin.com>

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: 2087e85bb66e ("spi: cadence-quadspi: fix suspend-resume implementations")
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/spi/spi-cadence-quadspi.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index 74647dfcb86c..d19ba024c80b 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1930,10 +1930,9 @@ static void cqspi_remove(struct platform_device *pdev)
 static int cqspi_suspend(struct device *dev)
 {
 	struct cqspi_st *cqspi = dev_get_drvdata(dev);
-	struct spi_controller *host = dev_get_drvdata(dev);
 	int ret;
 
-	ret = spi_controller_suspend(host);
+	ret = spi_controller_suspend(cqspi->host);
 	cqspi_controller_enable(cqspi, 0);
 
 	clk_disable_unprepare(cqspi->clk);
@@ -1944,7 +1943,6 @@ static int cqspi_suspend(struct device *dev)
 static int cqspi_resume(struct device *dev)
 {
 	struct cqspi_st *cqspi = dev_get_drvdata(dev);
-	struct spi_controller *host = dev_get_drvdata(dev);
 
 	clk_prepare_enable(cqspi->clk);
 	cqspi_wait_idle(cqspi);
@@ -1953,7 +1951,7 @@ static int cqspi_resume(struct device *dev)
 	cqspi->current_cs = -1;
 	cqspi->sclk = 0;
 
-	return spi_controller_resume(host);
+	return spi_controller_resume(cqspi->host);
 }
 
 static DEFINE_RUNTIME_DEV_PM_OPS(cqspi_dev_pm_ops, cqspi_suspend,

-- 
2.43.2