| From fd7f51abb0a6cefd79a4fca77da2bfde0f0d7c2d Mon Sep 17 00:00:00 2001 |
| From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> |
| Date: Tue, 30 Apr 2019 10:52:29 -0500 |
| Subject: ACPI / property: fix handling of data_nodes in |
| acpi_get_next_subnode() |
| |
| [ Upstream commit 23583f7795025e3c783b680d906509366b0906ad ] |
| |
| When the DSDT tables expose devices with subdevices and a set of |
| hierarchical _DSD properties, the data returned by |
| acpi_get_next_subnode() is incorrect, with the results suggesting a bad |
| pointer assignment. The parser works fine with device_nodes or |
| data_nodes, but not with a combination of the two. |
| |
| The problem is traced to an invalid pointer used when jumping from |
| handling device_nodes to data nodes. The existing code looks for data |
| nodes below the last subdevice found instead of the common root. Fix |
| by forcing the acpi_device pointer to be derived from the same fwnode |
| for the two types of subnodes. |
| |
| This same problem of handling device and data nodes was already fixed |
| in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data |
| node parsing in acpi_get_next_subnode()")' but broken later by 'commit |
| 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so |
| this should probably go to linux-stable all the way to 4.12 |
| |
| Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> |
| Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> |
| Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/acpi/property.c | 8 ++++++++ |
| 1 file changed, 8 insertions(+) |
| |
| diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c |
| index 77abe0ec40431..bd533f68b1dec 100644 |
| --- a/drivers/acpi/property.c |
| +++ b/drivers/acpi/property.c |
| @@ -1031,6 +1031,14 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, |
| const struct acpi_data_node *data = to_acpi_data_node(fwnode); |
| struct acpi_data_node *dn; |
| |
| + /* |
| + * We can have a combination of device and data nodes, e.g. with |
| + * hierarchical _DSD properties. Make sure the adev pointer is |
| + * restored before going through data nodes, otherwise we will |
| + * be looking for data_nodes below the last device found instead |
| + * of the common fwnode shared by device_nodes and data_nodes. |
| + */ |
| + adev = to_acpi_device_node(fwnode); |
| if (adev) |
| head = &adev->data.subnodes; |
| else if (data) |
| -- |
| 2.20.1 |
| |
