patch "iio: adc: exynos-adc: Fix NULL pointer exception on unbind" added to staging-next

patch "iio: adc: exynos-adc: Fix NULL pointer exception on unbind" added to staging-next

[gregkh]

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

    iio: adc: exynos-adc: Fix NULL pointer exception on unbind

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


From 2ea8bab4dd2a9014e723b28091831fa850b82d83 Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: Sat, 9 Feb 2019 00:39:27 +0100
Subject: iio: adc: exynos-adc: Fix NULL pointer exception on unbind

Fix NULL pointer exception on device unbind when device tree does not
contain "has-touchscreen" property.  In such case the input device is
not registered so it should not be unregistered.

    $ echo "12d10000.adc" > /sys/bus/platform/drivers/exynos-adc/unbind

    Unable to handle kernel NULL pointer dereference at virtual address 00000474
    ...
    (input_unregister_device) from [<c0772060>] (exynos_adc_remove+0x20/0x80)
    (exynos_adc_remove) from [<c0587d5c>] (platform_drv_remove+0x20/0x40)
    (platform_drv_remove) from [<c05860f0>] (device_release_driver_internal+0xdc/0x1ac)
    (device_release_driver_internal) from [<c0583ecc>] (unbind_store+0x60/0xd4)
    (unbind_store) from [<c031b89c>] (kernfs_fop_write+0x100/0x1e0)
    (kernfs_fop_write) from [<c029709c>] (__vfs_write+0x2c/0x17c)
    (__vfs_write) from [<c0297374>] (vfs_write+0xa4/0x184)
    (vfs_write) from [<c0297594>] (ksys_write+0x4c/0xac)
    (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x28)

Fixes: 2bb8ad9b44c5 ("iio: exynos-adc: add experimental touchscreen support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/adc/exynos_adc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
index fa2d2b5767f3..41da522fc673 100644
--- a/drivers/iio/adc/exynos_adc.c
+++ b/drivers/iio/adc/exynos_adc.c
@@ -929,7 +929,7 @@ static int exynos_adc_remove(struct platform_device *pdev)
 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
 	struct exynos_adc *info = iio_priv(indio_dev);
 
-	if (IS_REACHABLE(CONFIG_INPUT)) {
+	if (IS_REACHABLE(CONFIG_INPUT) && info->input) {
 		free_irq(info->tsirq, info);
 		input_unregister_device(info->input);
 	}
-- 
2.20.1