Bug 1810153

Summary:	fix leaking device state in files in /run/NetworkManager/devices
Product:	Red Hat Enterprise Linux 8	Reporter:	Thomas Haller <thaller>
Component:	NetworkManager	Assignee:	Thomas Haller <thaller>
Status:	CLOSED ERRATA	QA Contact:	Desktop QE <desktop-qa-list>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	8.2	CC:	acardace, atragler, bgalvani, lmiksik, lrintel, rkhan, sukulkar, thaller, till, vbenes
Target Milestone:	rc
Target Release:	8.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	NetworkManager-1.22.8-4.el8	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-04-28 16:54:14 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Thomas Haller 2020-03-04 15:56:55 UTC

NetworkManager writes the device state to /run/NetworkManager/devices.

The filename of these devices, is the ifindex. That is good, because the ifindex uniquely identifies the file at an time (yes, in practice the ifindex can be repeated, but that is no problem here). Also, the data in /run is only relevant for the current boot -- just like the ifindex.

But NetworkManager would only cleanup stale files when quitting. Usually NetworkManager service is not stopped (except during shutdown/reboot). So, in practice, these files pile up until reboot.

When creating (and deleting) a large number of software devices, this becomes a problem.

Imagine docker/podman that creates veth devices for each container.


Fix that by pruning stale files (from time to time).

Comment 2 Thomas Haller 2020-03-04 16:10:10 UTC

reproducer:


```

Create() {
  printf "#%05d: create device \"test\"\n" "$1"
  ip link delete test &>/dev/null
  ip link add test type bridge
  ip addr add 192.168.193.166/24 dev test
  ip link set test up
  sleep 1
}

Create_n() {
  for i in $(seq 1 "$1"); do
    Create "$i"
  done
}

Create_n 100

```

At the end, look at 

  $ ls -la /run/NetworkManager/devices/


also, while it's running, look at

  $ watch 'ip link show dev test; ls -la /run/NetworkManager/devices/'

Comment 4 Thomas Haller 2020-03-04 16:17:58 UTC

upstream fix here: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/commit/76984a4af39dd01e5520eba569cd83d6459bc1f6

Comment 8 Vladimir Benes 2020-03-20 14:38:57 UTC

Test case 'clean_device_state_files' added.

Comment 10 errata-xmlrpc 2020-04-28 16:54:14 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:1847