What does "cpu lock-up" mean? and how should i debug this issue?

What does "cpu lock-up" mean? and how should i debug this issue?https://devzone.nordicsemi.com/f/nordic-q-a/32894/what-does-cpu-lock-up-mean-and-how-should-i-debug-this-issueDear All: My board will reset some time, and i print the register "RESETREAS", and It's value is 8, the PS says it is "cpu lock up detected", Could anyone tell me what will cause that issue, How should i solve that problem? Thanks in advanceen-USTelligent Community 13Tue, 03 Apr 2018 18:15:30 GMTRE: What does "cpu lock-up" mean? and how should i debug this issue?https://devzone.nordicsemi.com/thread/126706?ContentTypeID=1Tue, 03 Apr 2018 18:15:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:94dfcb73-4ebb-4d63-92fe-058e85568dafKenneth<p>Hi, you should possible check your hardfault handler, for instance a hardfault within the hardfault handler may cause reset by CPU lockup.</p><div style="clear:both;"></div>