[PATCH AUTOSEL for 4.14 13/51] spi: spi-axi: fix potential use-after-free after deregistration

From: alexander . levin
Date: Wed Nov 22 2017 - 18:01:14 EST


From: Johan Hovold <johan@xxxxxxxxxx>

[ Upstream commit 4d5e0689dc9d5640ad46cdfbe1896b74d8df1661 ]

Take an extra reference to the controller before deregistering it to
prevent use-after-free in the interrupt handler in case an interrupt
fires before the line is disabled.

Fixes: b1353d1c1d45 ("spi: Add Analog Devices AXI SPI Engine controller support")
Acked-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
drivers/spi/spi-axi-spi-engine.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-engine.c
index 6ab4c7700228..68cfc351b47f 100644
--- a/drivers/spi/spi-axi-spi-engine.c
+++ b/drivers/spi/spi-axi-spi-engine.c
@@ -553,7 +553,7 @@ static int spi_engine_probe(struct platform_device *pdev)

static int spi_engine_remove(struct platform_device *pdev)
{
- struct spi_master *master = platform_get_drvdata(pdev);
+ struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
struct spi_engine *spi_engine = spi_master_get_devdata(master);
int irq = platform_get_irq(pdev, 0);

@@ -561,6 +561,8 @@ static int spi_engine_remove(struct platform_device *pdev)

free_irq(irq, master);

+ spi_master_put(master);
+
writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET);
--
2.11.0