On Wed, Apr 11, 2018 at 6:24 PM, David Howells [off-list ref] wrote:

From: Kyle McMartin <redacted>

Make an option to provide a sysrq key that will lift the kernel lockdown,
thereby allowing the running kernel image to be accessed and modified.

On x86 this is triggered with SysRq+x, but this key may not be available on
all arches, so it is set by setting LOCKDOWN_LIFT_KEY in asm/setup.h.
Since this macro must be defined in an arch to be able to use this facility
for that arch, the Kconfig option is restricted to arches that support it.

In the current form, this is probably incompatible with USB/IP (which
Debian seems to be shipping as a module by default), right? And
perhaps also with dummy_hcd (if I understand correctly what it's
doing)?