ipv6_ready referenced before assignment

[ubuntu-server-builder]

This bug was originally filed in Launchpad as LP: #1987005

Launchpad details

affected_projects = []
assignee = akutz
assignee_name = Andrew Kutz
date_closed = 2022-12-12T13:57:23.063028+00:00
date_created = 2022-08-18T22:32:29.336307+00:00
date_fix_committed = 2022-08-22T19:09:12.247013+00:00
date_fix_released = 2022-12-12T13:57:23.063028+00:00
id = 1987005
importance = high
is_complete = True
lp_url = https://bugs.launchpad.net/cloud-init/+bug/1987005
milestone = None
owner = jerrychengca
owner_name = Jerry Cheng
private = False
status = fix_released
submitter = jerrychengca
submitter_name = Jerry Cheng
tags = []
duplicates = []

Launchpad user Jerry Cheng(jerrychengca) wrote on 2022-08-18T22:32:29.336307+00:00

cloud-init crashes due to reference ipv6_ready before assignment.
cloud-init version: 22.2.2-1.ph3

traceback in cloudinit/sources/DataSourceVMware.py:

[2022-08-15 17:38:14] 2022-08-15 17:38:14,682 - util.py[WARNING]: failed stage init

[2022-08-15 17:38:14] failed run of stage init

[2022-08-15 17:38:14] ------------------------------------------------------------

[2022-08-15 17:38:14] Traceback (most recent call last):

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/cmd/main.py", line 740, in status_wrapper

[2022-08-15 17:38:14] ret = functor(name, args)

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/cmd/main.py", line 429, in main_init

[2022-08-15 17:38:14] init.setup_datasource()

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/stages.py", line 468, in setup_datasource

[2022-08-15 17:38:14] self.datasource.setup(is_new_instance=self.is_new_instance())

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/sources/DataSourceVMware.py", line 340, in setup

[2022-08-15 17:38:14] host_info = wait_on_network(self.metadata)

[2022-08-15 17:38:14] File "/usr/lib/python3.7/site-packages/cloudinit/sources/DataSourceVMware.py", line 963, in wait_on_network

[2022-08-15 17:38:14] ipv6_ready,

[2022-08-15 17:38:14] UnboundLocalError: local variable 'ipv6_ready' referenced before assignment

There is an issue in the source code: under certain conditions, ipv6_ready may be referenced in LOG.debug() before assignment if wait_on_ipv6 = false. The same issue may also happen for ipv4_ready if wait_on_ipv4 = false.

host_info = None

while host_info is None:

    # This loop + sleep results in two logs every second while waiting

    # for either ipv4 or ipv6 up. Do we really need to log each iteration

    # or can we log once and log on successful exit?

    host_info = get_host_info()



    network = host_info.get("network") or {}

    interfaces = network.get("interfaces") or {}

    by_ipv4 = interfaces.get("by-ipv4") or {}

    by_ipv6 = interfaces.get("by-ipv6") or {}



    if wait_on_ipv4:

        ipv4_ready = len(by_ipv4) > 0 if by_ipv4 else False

        if not ipv4_ready:

            host_info = None



    if wait_on_ipv6:

        ipv6_ready = len(by_ipv6) > 0 if by_ipv6 else False

        if not ipv6_ready:

            host_info = None



    if host_info is None:

        LOG.debug(

            "waiting on network: wait4=%s, ready4=%s, wait6=%s, ready6=%s",

            wait_on_ipv4,

            ipv4_ready,

            wait_on_ipv6,

            ipv6_ready,

        )

        time.sleep(1)

[ubuntu-server-builder]

Launchpad user Andrew Kutz(akutz) wrote on 2022-08-19T13:55:22.598106+00:00

Opened PR to fix the issue -- #1674

[ubuntu-server-builder]

Launchpad user Chad Smith(chad.smith) wrote on 2022-08-22T19:11:17.429794+00:00

Thanks Andrew for the upstream commit here.
9f0efc4

This will be in cloud-init the next cloud-init SRU of 22.3-X which should also make it into Ubuntu Bionic, Focal and Jammy in the next 2 weeks.

I realize this doesn't help Photon OS, but wanted to provide a reference in case this hits Ubuntu consumers too.