Re: [PATCH] ACPI / property: fix handling of data_nodes in acpi_get_next_subnode()

[Rafael J. Wysocki]

On Tue, Apr 30, 2019 at 5:52 PM Pierre-Louis Bossart
<pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxxxxx>

Applied with the Andy's R-by, but I reformatted the comment to take
fewer lines of code.

Thanks!