The question about ".reg-xstate"

Hi all,

Greetings from me!

I am using gdb to debug a core dump file, and it prompts following warnings:

.....
warning: Unexpected size of section `.reg-xstate/147393' in core file.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `./client'.
Program terminated with signal SIGABRT, Aborted.
......

Could anyone explain what is the function of ".reg-xstate"? Does this
warning mean this is an incomplete core dump file?

Thanks very much in advance!

Best Regards
Nan Xiao