withSockStats may be called before setLinkMonitor, in which case we
don't have a populated knownInterfaces map. Since we pre-populate the
per-interface counters at creation time, we would end up with an
empty map. To mitigate this, we do an on-demand request for the list of
interfaces.
This would most often happen with the logtail instrumentation, since we
initialize it very early on.
Updates tailscale/corp#9230
Signed-off-by: Mihai Parparita <mihai@tailscale.com>
4c2f67a1d0