acpi: set up the sysctl tree before acpi_machdep_init()

[nprice]

Summary

On amd64 and i386, acpi_machdep_init() adds hw.acpi.reset_video under
acpi_sysctl_tree. Since the tree moved to the end of attach, it no
longer exists at that point, so sysctl_add_oid() drops the node and the
sysctl documented in acpi(4) is missing. Found with KUBSAN.

acpi_machdep_init() cannot fail, so calling it after the tree does not
leave knobs behind on a failed attach.

Signed-off-by: Nick Price <[e-mail]>

[olce]

Oh, sorry to have missed that. Building the sysctl(8) tree was pushed down in order to avoid having to add code to destroy it on error as at this point error is not possible anymore. Thus, just moving the call to acpi_machdep_init() is not enough. You have to add a call to syctl_ctx_free() on error.

When this revision is approved, please add the following tag on commit:
Fixes: 7f031c9f6b9f ("acpi: Move sysctl tree set up at end of initialization")