network: fix crash when Wi-Fi or eth interface gets removed from the system #1789
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…system
When a network interface is disconnected from the system (e.g.,
physically removed if it's a USB adapter), probert asynchronously calls
the del_link() method.
Upon receiving this notification, Subiquity server wants to send an
update to the Subiquity clients. The update contains information about
the interface that disappeared - which is obtained through a call to
netdev_info.
Unfortunately, for Wi-Fi and Ethernet interfaces, netdev_info
dereferences the NetworkDev.info variable. Interfaces that no longer
exist on the system (and also interfaces that do not yet exist), have
their "info" variable set to None - so an exception is raised when
dereferencing it.
Wi-Fi interface:
File "subiquitycore/models/network.py", line 227, in netdev_info
scan_state=self.info.wlan['scan_state'],
AttributeError: 'NoneType' object has no attribute 'wlan'
Ethernet interface:
File "subiquitycore/models/network.py", line 201, in netdev_info
is_connected = bool(self.info.is_connected)
AttributeError: 'NoneType' object has no attribute 'is_connected'
Fixed by making sure netdev_info does not raise if the dev.info variable
is None. This is a valid use-case.
Signed-off-by: Olivier Gayot <olivier.gayot@canonical.com>
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mwhudson
approved these changes
Sep 7, 2023
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Addresses https://bugs.launchpad.net/subiquity/+bug/2012659 and other private bugs with similar stracktraces.
When a network interface is disconnected from the system (e.g., physically removed if it's a USB adapter), probert asynchronously calls the del_link() method.
Upon receiving this notification, Subiquity server wants to send an update to the Subiquity clients. The update contains information about the interface that disappeared - which is obtained through a call to netdev_info.
Unfortunately, for Wi-Fi and Ethernet interfaces, netdev_info dereferences the NetworkDev.info variable. Interfaces that no longer exist on the system (and also interfaces that do not yet exist), have their "info" variable set to None - so an exception is raised when dereferencing it.
Wi-Fi interface:
Ethernet interface:
Fixed by making sure netdev_info does not raise if the dev.info variable is None. This is a valid use-case.
NOTE: The crash could occur very early - even when the user is still on the welcome screen - and for Wi-Fi or Ethernet interface (even if it is essentially unused).
During testing, I noticed that a crash would still occur if the network interface get disconnected while the user is on the network screen. The stacktrace is different and I will address it in a follow-on PR (possibly with a different LP).