Comment # 19 on bug 1184924 from Ivan Ivanov

(In reply to Fabian Vogt from comment #14)
> [    0.000000] Unable to handle kernel NULL pointer dereference at virtual
> address 0000000000000000
> [    0.000000] Mem abort info:
> [    0.000000]   ESR = 0x96000004
> [    0.000000]   Exception class = DABT (current EL), IL = 32 bits
> [    0.000000]   SET = 0, FnV = 0
> [    0.000000]   EA = 0, S1PTW = 0
> [    0.000000] Data abort info:
> [    0.000000]   ISV = 0, ISS = 0x00000004
> [    0.000000]   CM = 0, WnR = 0
> [    0.000000] [0000000000000000] user address but active_mm is swapper
> [    0.000000] Internal error: Oops: 96000004 [#1] SMP
> [    0.000000] Modules linked in:
> [    0.000000] Supported: Yes
> [    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.3.18-59.24-default
> #1 SLE15-SP3
> [    0.000000] pstate: 60000085 (nZCv daIf -PAN -UAO)
> [    0.000000] pc : kthread_should_stop+0x2c/0x60

The NULL pointer is current->set_child_tid. 

For SLE15-SP3 CONFIG_RANDOM_TRUST_BOOTLOADER option is enabled
only for armv7h and arm64.

For 'stable' same option is enabled for all other arches except Arm :-)

If we do same tests for non-Arm arches and they are passing then
something in arch setup code is not Ok. If we don't do these tests
then CONFIG_RANDOM_TRUST_BOOTLOADER is broken since inception.