100% CPU usage for Network Manager process, may be due to IPv6 neighbor discovery
I recently find that NetworkManager process will take 100% CPU (one CPU thread) for no obvious reason.
I have changed the log level to DEBUG, and around the 100% CPU usage duration, the only interesting event is: adam-pc NetworkManager: [1550140076.3784] ndisc-lndp[0x560ac3ce50e0,"eth0"]: processing libndp events
And strace only shows NetworkManager is writing tons of "\1\0\0\0\0\0\0\0" to fd 3, however since I'm attaching to running NetworkManager, I can't know where fd 3 is binded. From procfs, fd 3 of that running NetworkManager process is just an anonymous inode.
Now I have disabled IPv6 completely and sees no problem for over 1 day. But I really hope to use IPv6, have tried "auto (DHCP only)", that seems to ignore neighbor discovery, but also ignored my default route advertising. "Auto (address only)" makes my default route work, but also accepts neighbor discovery.
How can I further pinning down the bug?
The version of NM is 1.14.5dev+17+gba83251b-2.