Kernel crash when enable debug mode [dattobd 0.12.1]

[yito24]

It is 100% reproducible.

Step

1. Build with debug enabled
   dattobd_debug = 1
2. install dattobd
3. run timedatectl
   When kdump is enabled
   ---> kernel crash
   When kdump is disabled
   ---> OS hang
4. After a forced power off, OS does not boot.
   Stop in this state.
   

This issue is also referenced in this case.
#410

This is the vmcore-dmesg of CentOS7.9.
vmcore-dmesg.txt

In my testing, the OS crashes, hangs, or does not boot on relatively old kernels.
Note that this does not occur on Debian9 (kernel 4.9.0.x)

• RHEL7.x and RHEL7.x Clone OS (kernel 3.10.0.x )
• Debian10 (kernel 4.19.0.x)
• Ubuntu18.04 (kernel 5.4.0.x)