[CentOS] CentOS 7 system running out of available memory, then unusable, network interfaces probably involved

Mon Jun 29 19:45:46 UTC 2020
wwp <subscript at free.fr>

Hello,

my CentOS 7 system goes unstable after few days of use, memory
consumption growing and never getting freed, until the system slows
down to hell (swapping), kills apps, and eventually freezes or reboots
itself.

This only happens when I have two network interfaces turned on, one
wired and one wireless, each to different routers.

The hardware: a Dell Precision 7530, SSD, 16GB RAM. HW memory and disk
both tested OK by software.
According to lspci:
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (7) I219-LM (rev 10)
6e:00.0 Network controller: Intel Corporation Wireless-AC 9260 (rev 29)

The software: I keep this CentOS 7 system up-to-date with the CR repo,
excepted the microcode_ctl package, stuck to few versions back
(updating it kills the system and potentially causes fs damages).
Kernels reproducing the issue (IOW, all):
  kernel-3.10.0-1062.18.1.el7.x86_64
  kernel-3.10.0-1127.el7.x86_64
  kernel-3.10.0-1127.8.2.el7.x86_64
  kernel-3.10.0-1127.13.1.el7.x86_64

Nothing jumps to my eyes looking at /var/log/messages but this, many
occurrences:
  kernel: nf_conntrack: falling back to vmalloc.
I searched the Internet for it, and the few results I found were
not bringing any solution and were quite pessimistic WRT to memory
freeing, am I wrong?

Regards,

-- 
wwp
https://useplaintext.email/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 836 bytes
Desc: OpenPGP digital signature
URL: <http://lists.centos.org/pipermail/centos/attachments/20200629/57b04f28/attachment.sig>