From 07bb9a71ee27929127f0dd434edaa9f22e378884 Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Tue, 30 Apr 2019 10:52:29 -0500 Subject: [PATCH] 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 Reviewed-by: Andy Shevchenko Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/property.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c index 693cf05..288673c 100644 --- a/drivers/acpi/property.c +++ b/drivers/acpi/property.c @@ -975,6 +975,14 @@ 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) -- 2.7.4