Commit 0aef44e8 authored Sep 12, 2014 by Peter Hüwe Committed by Wolfram Sang Sep 25, 2014

i2c: acpi: Fix NULL Pointer dereference



If adapter->dev.parent == NULL there is a NULL pointer dereference in
acpi_i2c_install_space_handler and acpi_i2c_remove_space_handler.

This is present since introduction of this code:
36604751 "i2c: rework kernel config I2C_ACPI" or even
da3c6647 "I2C/ACPI: Clean up I2C ACPI code and Add CONFIG_I2C_ACPI"

The adapter->dev.parent == NULL case is valid for the i2c_stub,
so loading i2c_stub with ACPI_I2C_OPREGION enabled results in an oops.
This is also valid at least for i2c_tiny_usb and i2c_robotfuzz_osif.

Fix by checking whether it is null before calling ACPI_HANDLE.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

parent 17f4a5c4

drivers/i2c/i2c-core.c

+12 −2

Original line number	Diff line number	Diff line
		@@ -371,10 +371,15 @@ acpi_i2c_space_handler(u32 function, acpi_physical_address command,

		static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
		{
		acpi_handle handle = ACPI_HANDLE(adapter->dev.parent);
		acpi_handle handle;
		struct acpi_i2c_handler_data *data;
		acpi_status status;

		if (!adapter->dev.parent)
		return -ENODEV;

		handle = ACPI_HANDLE(adapter->dev.parent);

		if (!handle)
		return -ENODEV;

		@@ -407,10 +412,15 @@ static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)

		static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
		{
		acpi_handle handle = ACPI_HANDLE(adapter->dev.parent);
		acpi_handle handle;
		struct acpi_i2c_handler_data *data;
		acpi_status status;

		if (!adapter->dev.parent)
		return;

		handle = ACPI_HANDLE(adapter->dev.parent);

		if (!handle)
		return;