Patch "spi: spi-axi: fix potential use-after-free after deregistration" has been added to the 4.9-stable tree

Patch "spi: spi-axi: fix potential use-after-free after deregistration" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    spi: spi-axi: fix potential use-after-free after deregistration

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     spi-spi-axi-fix-potential-use-after-free-after-deregistration.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Dec  6 17:39:55 CET 2017
From: Johan Hovold <johan@kernel.org>
Date: Mon, 30 Oct 2017 11:35:27 +0100
Subject: spi: spi-axi: fix potential use-after-free after deregistration

From: Johan Hovold <johan@kernel.org>


[ 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@metafoo.de>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/spi/spi-axi-spi-engine.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/spi/spi-axi-spi-engine.c
+++ b/drivers/spi/spi-axi-spi-engine.c
@@ -553,7 +553,7 @@ err_put_master:
 
 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 plat
 
 	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);


Patches currently in stable-queue which might be from johan@kernel.org are

queue-4.9/staging-greybus-loopback-fix-iteration-count-on-async-path.patch
queue-4.9/spi-spi-axi-fix-potential-use-after-free-after-deregistration.patch
queue-4.9/usb-serial-option-add-quectel-bg96-id.patch