Comment 51 for bug 1518457

I really tried hard DD'ing and filling up RAM but I really can not reproduce the issue under Ubuntu 15.04 on AWS EC2 nano. On my home server boxes that issue also didn't appear on Ubuntu 15.04 either - so I really think it was introduced between 15.04 and 15.10.

Linux ip-172-31-7-84 3.19.0-20-generic #20-Ubuntu SMP Fri May 29 10:10:47 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

root@ip-172-31-7-84:/home/ubuntu# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=15.04
DISTRIB_CODENAME=vivid
DISTRIB_DESCRIPTION="Ubuntu 15.04"

top - 19:17:38 up 45 min, 2 users, load average: 3.52, 2.91, 1.93
Tasks: 87 total, 3 running, 84 sleeping, 0 stopped, 0 zombie
%Cpu(s): 36.4 us, 13.3 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 50.3 st
KiB Mem: 499128 total, 492924 used, 6204 free, 8552 buffers
KiB Swap: 1048572 total, 18664 used, 1029908 free. 136340 cached Mem

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
11405 root 20 0 127120 124140 1360 R 36.6 24.9 3:19.84 memtester
11425 root 20 0 168080 165052 1340 R 36.0 33.1 3:09.11 memtester
11797 root 20 0 7012 2724 1660 D 16.6 0.5 0:54.64 dd
12110 root 20 0 7012 2792 1728 D 7.7 0.6 0:01.19 dd
 1190 root 20 0 0 0 0 D 2.0 0.0 0:00.98 kworker/u30+
   32 root 20 0 0 0 0 S 1.0 0.0 0:01.62 kswapd0
    1 root 20 0 35032 2020 1476 S 0.0 0.4 0:01.68 systemd
    2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
    3 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
    5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
    7 root 20 0 0 0 0 S 0.0 0.0 0:00.67 rcu_sched
    8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh

[...]

Total DISK READ : 3.88 K/s | Total DISK WRITE : 67.48 M/s
Actual DISK READ: 3.88 K/s | Actual DISK WRITE: 65.99 M/s
  TID PRIO USER DISK READ DISK WRITE> SWAPIN IO COMMAND
12110 be/4 root 0.00 B/s 67.48 M/s 0.00 % 86.28 % dd if=/de~0096 bs=1M
    1 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % init
    2 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kthreadd]
    3 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [ksoftirqd/0]
    5 be/0 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [kworker/0:0H]
    7 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [rcu_sched]
    8 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.00 % [rcu_bh]

[...]