container gets oom killed every now and then when mem usage is low

[ibigbug]

Hi,

I have a PiHole running on PVE inside a lxc, it was running fine for a while but recently it's getting killed every few minutes when the memory usage of the container and the PVE host if relatively low

any ideas how to debug?

thanks

root@pve:~# cat /etc/pve/lxc/100.conf
arch: amd64
cores: 1
hostname: pihole
memory: 1024
nameserver: 127.0.0.1
net0: name=eth0,bridge=vmbr0,firewall=1,gw=10.0.1.2,hwaddr=8E:44:6A:30:A2:8C,ip=10.0.1.5/24,type=veth
onboot: 1
ostype: debian
rootfs: local-lvm:vm-100-disk-0,size=8G
searchdomain: x
swap: 512
unprivileged: 1

root@pve:~# pveversion -v
proxmox-ve: 6.2-2 (running kernel: 5.4.65-1-pve)
pve-manager: 6.2-12 (running version: 6.2-12/b287dd27)
pve-kernel-5.4: 6.2-7
pve-kernel-helper: 6.2-7
pve-kernel-5.4.65-1-pve: 5.4.65-1
pve-kernel-5.4.60-1-pve: 5.4.60-2
pve-kernel-5.4.34-1-pve: 5.4.34-2
ceph-fuse: 12.2.11+dfsg1-2.1+b1
corosync: 3.0.4-pve1
criu: 3.11-3
glusterfs-client: 5.5-3
ifupdown: 0.8.35+pve1
ksm-control-daemon: 1.3-1
libjs-extjs: 6.0.1-10
libknet1: 1.16-pve1
libproxmox-acme-perl: 1.0.5
libpve-access-control: 6.1-2
libpve-apiclient-perl: 3.0-3
libpve-common-perl: 6.2-2
libpve-guest-common-perl: 3.1-3
libpve-http-server-perl: 3.0-6
libpve-storage-perl: 6.2-6
libqb0: 1.0.5-1
libspice-server1: 0.14.2-4~pve6+1
lvm2: 2.03.02-pve4
lxc-pve: 4.0.3-1
lxcfs: 4.0.3-pve3
novnc-pve: 1.1.0-1
proxmox-backup-client: 0.9.0-1
proxmox-mini-journalreader: 1.1-1
proxmox-widget-toolkit: 2.2-12
pve-cluster: 6.1-8
pve-container: 3.2-2
pve-docs: 6.2-6
pve-edk2-firmware: 2.20200531-1
pve-firewall: 4.1-3
pve-firmware: 3.1-3
pve-ha-manager: 3.1-1
pve-i18n: 2.2-1
pve-qemu-kvm: 5.1.0-2
pve-xtermjs: 4.7.0-2
qemu-server: 6.2-14
smartmontools: 7.1-pve2
spiceterm: 3.1-1
vncterm: 1.6-2
zfsutils-linux: 0.8.4-pve1

[500156.783121] DNS client invoked oom-killer: gfp_mask=0xcc0(GFP_KERNEL), order=0, oom_score_adj=0
[500156.783123] CPU: 2 PID: 32168 Comm: DNS client Tainted: P        W  O      5.4.65-1-pve #1
[500156.783123] Hardware name: BIOSTAR Group B250GT3/B250GT3, BIOS 5.12 01/07/2020
[500156.783124] Call Trace:
[500156.783129]  dump_stack+0x6d/0x9a
[500156.783130]  dump_header+0x4f/0x1e1
[500156.783131]  oom_kill_process.cold.33+0xb/0x10
[500156.783132]  out_of_memory+0x1ad/0x490
[500156.783134]  mem_cgroup_out_of_memory+0xc4/0xd0
[500156.783136]  try_charge+0x76b/0x7e0
[500156.783138]  ? __alloc_pages_nodemask+0x16a/0x330
[500156.783139]  mem_cgroup_try_charge+0x71/0x190
[500156.783141]  mem_cgroup_try_charge_delay+0x22/0x50
[500156.783142]  wp_page_copy+0x11c/0x750
[500156.783144]  ? record_times+0x1b/0x90
[500156.783145]  ? reuse_swap_page+0x144/0x330
[500156.783147]  do_wp_page+0x91/0x680
[500156.783148]  __handle_mm_fault+0xbb5/0x12e0
[500156.783149]  handle_mm_fault+0xc9/0x1f0
[500156.783151]  __do_page_fault+0x233/0x4c0
[500156.783152]  do_page_fault+0x2c/0xe0
[500156.783154]  page_fault+0x34/0x40
[500156.783156] RIP: 0010:copy_user_generic_unrolled+0x89/0xc0
[500156.783157] Code: 38 4c 89 47 20 4c 89 4f 28 4c 89 57 30 4c 89 5f 38 48 8d 76 40 48 8d 7f 40 ff c9 75 b6 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 <4c> 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a
[500156.783158] RSP: 0000:ffffbe328944fe50 EFLAGS: 00050202
[500156.783159] RAX: 00007ff2c0cbeec0 RBX: 0000000000000000 RCX: 0000000000000002
--
[500156.783222] oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=ns,mems_allowed=0,oom_memcg=/lxc/100,task_memcg=/lxc/100/ns/user.slice/user-998.slice/session-c10.scope,task=pihole-FTL,pid=32162,uid=100998
[500156.783232] Memory cgroup out of memory: Killed process 32162 (pihole-FTL) total-vm:401088kB, anon-rss:19520kB, file-rss:0kB, shmem-rss:264kB, UID:100998 pgtables:132kB oom_score_adj:0
[500156.783953] oom_reaper: reaped process 32162 (pihole-FTL), now anon-rss:0kB, file-rss:0kB, shmem-rss:268kB
[500160.491897] audit: type=1325 audit(1602133220.840:147230): table=filter family=7 entries=0

Mem of host:




Mem of container:

 

[felon]

would be nice to hear something about it because we are running into an issue that 2-4 containers have problems regarding oom-killer