linux-kernel - [PATCH RESEND] spi: erase pointer to drvdata on removal

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Message-Id: <1354566504-17657-1-git-send-email-vivien.didelot@savoirfairelinux.com>
Date:	Mon,  3 Dec 2012 15:28:24 -0500
From:	Vivien Didelot <vivien.didelot@...oirfairelinux.com>
To:	spi-devel-general@...ts.sourceforge.net
Cc:	Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
	Rob Herring <rob.herring@...xeda.com>,
	Grant Likely <grant.likely@...retlab.ca>,
	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH RESEND] spi: erase pointer to drvdata on removal

Without this patch, a SPI device may keep its drvdata whereas it was unbound
from its driver. This may result in accessing an invalid pointer.

As for i2c-core, let the SPI core handle the removal of the device's drvdata,
after a remove(), or a probe() failure.

This is a resent of the previous patch https://lkml.org/lkml/2012/11/1/314

Signed-off-by: Vivien Didelot <vivien.didelot@...oirfairelinux.com>
---
 drivers/spi/spi.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 84c2861..fe636fe 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -233,15 +233,25 @@ EXPORT_SYMBOL_GPL(spi_bus_type);
 static int spi_drv_probe(struct device *dev)
 {
 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
+	struct spi_device		*sdev = to_spi_device(dev);
+	int				status;
 
-	return sdrv->probe(to_spi_device(dev));
+	status = sdrv->probe(sdev);
+	if (status)
+		spi_set_drvdata(sdev, NULL);
+	return status;
 }
 
 static int spi_drv_remove(struct device *dev)
 {
 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
+	struct spi_device		*sdev = to_spi_device(dev);
+	int				status;
 
-	return sdrv->remove(to_spi_device(dev));
+	status = sdrv->remove(sdev);
+	if (status == 0)
+		spi_set_drvdata(sdev, NULL);
+	return status;
 }
 
 static void spi_drv_shutdown(struct device *dev)
-- 
1.7.11.7

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