RTNETLINK answers: Invalid argument

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This article/section is a stub — probably a pile of half-sorted notes and assertions some of which may well be wrong, and not verified as a whole. Feel free to add or refine.

...often in response to some use of the ip command, such as ip link set lo up

Can have various causes, largely depending on which command failed.

From anecdotal evidence, a relatively common cause seems to be interaction between having traffic shaping installed and certain versions of iproute2. If iproute2 is indeed the culprit, a slight upgrade or downgrade may fix it temporarily (usually enough until it is fixed in the next package version).