5.3-BETA1 panic with getnewbuf: locked buf

[Kachun Lee]

 >The server (E7501 single XEON 4G RAM) that I upgraded from 4.10 to 
5.3-BETA few days >ago panic'ed twice on 'getnewbuf: locked buf'. I 
included the backtrace and dmesg below. I >searched the lists and found 
several similar instances mentioned. Anything I can help to >find the 
problem. Thanks in advance for any help.

I forget to mention that I already rebuilt its kernel with 1.75 kern_lock.c 
(from current).

Regards
Kachun