Traced why a device that's alive and USB-enumerating correctly could still
never complete a single protocol handshake, indefinitely: journal logs
showed genuinely concurrent connection attempts on the same port
(duplicate "Opened serial port"/"Starting X handshake" lines within
microseconds of each other, from what should be sequential probe steps) —
two independent listener sessions were racing on the same tty, each
corrupting the other's reads/writes.
Root cause was in MeshService::stop() combined with mesh::flash's earlier
STOP_LISTENER_TIMEOUT fix: stop() calls `self.listener_handle.take()`
(clearing the field to None immediately) and then awaits the handle with
no bound of its own. When a caller wraps the whole stop() call in a
timeout (as the flash job does, to avoid hanging the RPC response), a slow
listener — mid multi-candidate probe when the shutdown signal arrives —
would cause that outer timeout to cancel the await. But by then
`listener_handle` was already None, so MeshService believed the listener
was stopped, while the actual task kept running, orphaned (dropping a
JoinHandle does not abort the task). A later start() then spawned a
genuinely new listener, racing the orphaned one forever on the same port.
Fixed at the source: stop() now awaits its own handle through a mutable
reference (not by value) with its own bounded timeout, so on timeout it
still owns the handle and can call .abort() on it directly — guaranteeing
the task is actually gone before stop() returns, regardless of how any
caller wraps it.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
(cherry picked from commit b14af20d1acfc053957ec22234773b5c59582a66)
ssmithx
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