Hit a strange signal settings of a kernel thread in Linux

I am working on an embedded Linux system (kernel-5.10.24), and using busybox as init. Now I hit a strange problem about signal settings of a kernel thread in system. The kernel thread is from a device driver, and by cat /proc/pid/status, I found its signal settings are as follows,

SigQ:   0/31126
SigPnd: 0000000000000000
ShdPnd: 0000000000004000
SigBlk: 0000000000000000
SigIgn: ffffffffffffbfff
SigCgt: 0000000000004000

Other kernel threads have 0xffffffffffffffff of SigIgn. The kernel thread is started with kthread_run() as other threads do. The setting of SigCgt and ShdPnd make the kernel thread unable to go into waiting status, instead, the kernel thread now is in a busy-loop on down_interruptible. So I am wondering is it correct about the kernel thread's signal settings? Where are the signal settings configured for kernel thread, is it possible for me to customize this settings, if so, how to??