[added to the 3.18 stable tree] Input: max8997-haptic - fix NULL pointer dereference

Sasha Levin
2016-05-19T04:18:11Z

From: Marek Szyprowski <m.szyprowski@samsung.com>

This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit 6ae645d5fa385f3787bf1723639cd907fe5865e7 ]

NULL pointer derefence happens when booting with DTB because the
platform data for haptic device is not set in supplied data from parent
MFD device.

The MFD device creates only platform data (from Device Tree) for itself,
not for haptic child.

Unable to handle kernel NULL pointer dereference at virtual address 0000009c
pgd = c0004000
[0000009c] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
(max8997_haptic_probe) from [<c03f9cec>] (platform_drv_probe+0x4c/0xb0)
(platform_drv_probe) from [<c03f8440>] (driver_probe_device+0x214/0x2c0)
(driver_probe_device) from [<c03f8598>] (__driver_attach+0xac/0xb0)
(__driver_attach) from [<c03f67ac>] (bus_for_each_dev+0x68/0x9c)
(bus_for_each_dev) from [<c03f7a38>] (bus_add_driver+0x1a0/0x218)
(bus_add_driver) from [<c03f8db0>] (driver_register+0x78/0xf8)
(driver_register) from [<c0101774>] (do_one_initcall+0x90/0x1d8)
(do_one_initcall) from [<c0a00dbc>] (kernel_init_freeable+0x15c/0x1fc)
(kernel_init_freeable) from [<c06bb5b4>] (kernel_init+0x8/0x114)
(kernel_init) from [<c0107938>] (ret_from_fork+0x14/0x3c)

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: <stable@vger.kernel.org>
Fixes: 104594b01ce7 ("Input: add driver support for MAX8997-haptic")
[k.kozlowski: Write commit message, add CC-stable]
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
drivers/input/misc/max8997_haptic.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/input/misc/max8997_haptic.c b/drivers/input/misc/max8997_haptic.c
index a363ebb..57f3d90 100644
--- a/drivers/input/misc/max8997_haptic.c
+++ b/drivers/input/misc/max8997_haptic.c
@@ -255,12 +255,14 @@ static int max8997_haptic_probe(struct platform_device *pdev)
struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
const struct max8997_platform_data *pdata =
dev_get_platdata(iodev->dev);
- const struct max8997_haptic_platform_data *haptic_pdata =
- pdata->haptic_pdata;
+ const struct max8997_haptic_platform_data *haptic_pdata = NULL;
struct max8997_haptic *chip;
struct input_dev *input_dev;
int error;

+ if (pdata)
+ haptic_pdata = pdata->haptic_pdata;
+
if (!haptic_pdata) {
dev_err(&pdev->dev, "no haptic platform data\n");
return -EINVAL;
--
2.5.0