l2cap: Resolve teardown hang on disconnect collision or abort#937
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…ze and setting asyncio_mode
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Jun 16, 2026
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| def abort(self) -> None: | ||
| if self.state == self.State.CONNECTED: | ||
| if self.state == self.State.CONNECTED or self.state == self.State.DISCONNECTING: |
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| if self.state == self.State.CONNECTED or self.state == self.State.DISCONNECTING: | |
| if self.state in (self.State.CONNECTED, self.State.DISCONNECTING): |
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| le_connection_channels = self.le_coc_channels.get(channel.connection.handle) | ||
| if le_connection_channels: | ||
| if le_connection_channels.get(channel.destination_cid) is channel: | ||
| del le_connection_channels[channel.destination_cid] |
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| le_connection_channels = self.le_coc_channels.get(channel.connection.handle) | |
| if le_connection_channels: | |
| if le_connection_channels.get(channel.destination_cid) is channel: | |
| del le_connection_channels[channel.destination_cid] | |
| self.le_coc_channels.pop(channel.connection.handle, None) |
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did you mean:
le_connection_channels = self.le_coc_channels.get(channel.connection.handle)
if le_connection_channels:
self.le_coc_channels.pop(channel.connection.handle, None)or you intend to remove the whole channel associated with that connection handle
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No, we just need to remove a single channel. However, considering that a handle is impossible to be a key of channels and le_coc_channels at the same time, we can just
def on_channel_closed(self, channel: ClassicChannel | LeCreditBasedChannel) -> None:
if classic_connection_channels := self.channels.get(channel.connection.handle):
classic_connection_channels.pop(channel.source_cid, None)
elif le_connection_channels := self.le_coc_channels.get(channel.connection.handle):
le_connection_channels.pop(channel.destination_cid, None)| connection_channels = self.channels.get(channel.connection.handle) | ||
| if connection_channels: | ||
| if channel.source_cid in connection_channels: | ||
| if connection_channels.get(channel.source_cid) is channel: |
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| if connection_channels.get(channel.source_cid) is channel: | |
| connection_channels.pop(channel.source_cid, None) |
| self._change_state(self.State.DISCONNECTED) | ||
| self.manager.on_channel_closed(self) | ||
| if was_disconnecting and self.disconnection_result: | ||
| self.disconnection_result.set_result(None) |
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I think we can just set connection_result and disconnection_result under any state?
| was_disconnecting = self.state == self.State.DISCONNECTING | ||
| self._change_state(self.State.DISCONNECTED) | ||
| self.manager.on_channel_closed(self) | ||
| if was_disconnecting and self.disconnection_result: |
Resolve a teardown hang in LeCreditBasedChannel. When a disconnection collision occurs (both DUT and peer call disconnect simultaneously) or the channel is aborted during disconnection, the connection state transitions to DISCONNECTED before the peer's response arrives (or is ignored). In these cases, the `disconnection_result` future remained unresolved, causing any awaiting teardown task to hang. This patch ensures that calling abort() or receiving a disconnection request while in the DISCONNECTING state correctly resolves `disconnection_result` and cleans up the channel. Verification: Verified with a new unit test `test_abort_while_disconnecting` added to `tests/l2cap_test.py` that stubs a non-responsive peer and calls abort() during the DISCONNECTING state transition, confirming it completes immediately.
Also includes the test_disconnection_collision unit test.
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Resolve a teardown hang in LeCreditBasedChannel. When a disconnection collision occurs (both DUT and peer call disconnect simultaneously) or the channel is aborted during disconnection, the connection state transitions to DISCONNECTED before the peer's response arrives (or is ignored). In these cases, the
disconnection_resultfuture remained unresolved, causing any awaiting teardown task to hang.This patch ensures that calling abort() or receiving a disconnection request while in the DISCONNECTING state correctly resolves
disconnection_resultand cleans up the channel.Verification:
Verified with a new unit test
test_abort_while_disconnectingadded totests/l2cap_test.pythat stubs a non-responsive peer and calls abort() during the DISCONNECTING state transition, confirming it completes immediately.