Mongod is using 1 cpu core while doing absolutely nothing. There is nothing reading from , or writing to mongodb and yet 1 cpu core is at 100% (most of it is iowait)

Fri Dec 11 10:11:07 connection accepted from 192.168.7.142:49806 #2
Fri Dec 11 10:11:07 end connection 192.168.7.142:49806
Fri Dec 11 10:12:07 connection accepted from 192.168.7.142:49811 #3
Fri Dec 11 10:12:07 end connection 192.168.7.142:49811
Fri Dec 11 10:13:08 connection accepted from 192.168.7.142:44181 #4
Fri Dec 11 10:13:08 end connection 192.168.7.142:44181
Fri Dec 11 10:14:07 connection accepted from 192.168.7.142:44183 #5
Fri Dec 11 10:14:08 end connection 192.168.7.142:44183
Fri Dec 11 10:15:07 connection accepted from 192.168.7.142:44185 #6
Fri Dec 11 10:15:08 end connection 192.168.7.142:44185
Fri Dec 11 10:16:08 connection accepted from 192.168.7.142:44187 #7
Fri Dec 11 10:16:08 end connection 192.168.7.142:44187

stracing the process gives:

rt_sigreturn(0x16) = -1 EINTR (Interrupted system call)
ioctl(6, SNDCTL_TMR_TIMEBASE or TCGETS,

{B38400 opost isig -icanon -echo ...}

) = 0
ioctl(6, SNDCTL_TMR_CONTINUE or TCSETSF,

{B38400 opost isig icanon echo ...}

) = ? ERESTARTSYS (To be restarted)
— SIGTTOU (Stopped (tty output)) @ 0 (0) —

(the above output is constantly repeated)

Killing the process and starting it again returned to normal idle usage