Release OutputSweeper::pending_sweep flag on future drop#4598
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TheBlueMatt merged 1 commit intoMay 6, 2026
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`regenerate_and_broadcast_spend_if_necessary` used `pending_sweep: AtomicBool` as a single-runner gate but only cleared the flag with an unconditional `store(false)` *after* the inner future resolved. If the caller's future was dropped while the inner await was `Pending` — which `tokio::time::timeout`, `futures::select!`, manual `JoinHandle::abort`, etc. all do — the reset never ran, leaving the flag stuck `true` and every subsequent call to the function short-circuiting with `Ok(())`. Because `OutputSweeper` is what claims `SpendableOutputDescriptor`s back to the user's wallet after channel closure (including HTLC outputs with time-bounded recovery deadlines), a stuck flag turns into fund-loss exposure: time-sensitive HTLC sweeps simply stop happening, while every other code path keeps queueing new outputs to sweep, until the process is restarted. Replace the trailing `store(false)` with an RAII `PendingSweepGuard` whose `Drop` impl always releases the flag — covering normal return, error, and cancellation alike. Co-Authored-By: HAL 9000
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👋 Thanks for assigning @joostjager as a reviewer! |
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The implementation is correct and clean. Key verification points:
No issues found. |
TheBlueMatt
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Honestly not sure its worth committing the test for this, but whatever.
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Yeah, true, I was also on the fence whether to include it or not. |
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The asyncification of this API happened in 0.2, so no need to backport to 0.1. |
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Backported to 0.2 in #4683. |
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v0.2.3 - Jun 18, 2026 - "Through the Loupe" API Updates =========== * `DefaultMessageRouter` will now always generate blinded message paths that provide no privacy (where our node is the introduction node) for nodes with public channels. This works around an issue which will appear for any nodes with LND peers that enable onion messaging - such peers will refuse to forward BOLT 12 messages from unknown third parties, which most BOLT 12 payers rely on today (lightningdevkit#4647). * Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder` now maps 0-amounts to an amount of `None` (lightningdevkit#4324). Bug Fixes ========= * `Features::supports_zero_conf` no longer clears the `ZeroConf` features and `Features::requires_zero_conf` now correctly reports required, rather than supported, status (lightningdevkit#4517). * If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are still being completed asynchronously, further channel updates (e.g. forwarding another payment) are pending and the node restarts, the channel could have become stuck (lightningdevkit#4520). * The presence of unconfirmed transactions actually no longer causes `ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590). * LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282). * Dropping the future returned by `OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer results in future calls to the same method being spuriously ignored (lightningdevkit#4598). * Used async-receive offers are no longer refreshed on every timer tick once their refresh time is reached (lightningdevkit#4672). * `FilesystemStore::list_all_keys` will no longer fail if there are stale intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618). * When forwarding an HTLC while in a blinded path with proportional fees over 200%, LDK will no longer spuriously allow a forward that pays us 1 msat too little in fees (lightningdevkit#4697). * Fixed a rare case where a channel could get stuck on reconnect when using both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684). * If we had exactly zero balance in a zero-fee-commitment channel, the counterparty was able to splice all of their balance out, violating the reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580). * Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no longer results in spuriously opening a channel early (lightningdevkit#4656). * `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where `ChannelManager::abandon_payment` was called before the payment ultimately completes anyway (lightningdevkit#4651). * `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey` for non-zero-commitment-fee anchor channels (lightningdevkit#4669). * Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544). * `OMDomainResolver` now correctly accounts for failed queries when rate limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591). * Calling `ChannelManager::send_payment_with_route` without a `route_params` and with an invalid `Route` will no longer panic (lightningdevkit#4707). * `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677). * `StaticInvoice::is_offer_expired` was corrected to check offer, rather than static invoice, expiry (lightningdevkit#4594). * `lightning-custom-message`'s handling of `peer_connected` events now ensures that sub-handlers will see a `peer_disconnected` event if a different sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595). * Replay protection for LSPS5 signatures now detects replays which are only different in the encoded signature's case (lightningdevkit#4701). * When `lightning-liquidity` is configured in the background processor, there is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246). * Incomplete MPP keysend payments will no longer see their HTLCs held until expiry (lightningdevkit#4558). * `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667). * `lightning-custom-message` handlers that return `Ok(None)` when asked to deserialize a message in their defined range no longer cause panics (lightningdevkit#4709). * Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026) Security ======== 0.2.3 fixes several underestimates of the anchor reserves required to ensure we can reliably close channels, several denial-of-service vulnerabilities and a sanitization issue. * `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an invoice which set an explicit public key, rather than relying on public key recovery. Note that this method is called from `PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717). * Maliciously-crafted unpayable invoices which have overflowing feerates will no longer cause an `unwrap` failure panic (lightningdevkit#4716). * Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is reachable when parsing messages from counterparties (lightningdevkit#4715). * `possiblyrandom` did not properly generate random data except when it was explicitly configured to. By default this means LDK is vulnerable to various HashDoS attacks (lightningdevkit#4719). * `OMNameResolver` will no longer panic when looking up payment instructions which include unicode characters at the start of a TXT record (lightningdevkit#4718). * When using the `anchor_channel_reserves` module to calculate reserves required to pay for fees when closing anchor channels, zero-fee-commitment channels were not considered. This could allow a counterparty to open many channels, leaving us unable to properly force-close (lightningdevkit#4592). * The `anchor_channel_reserves` module overestimated the value of `Utxo`s in the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670). * `PrintableString` did not properly sanitize unicode format characters, allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605). * RGS data is now limited in how large of a graph it is able to cause a client to store in memory. Note that RGS data is still considered a DoS vector in general and you should only use semi-trusted RGS data (lightningdevkit#4713). * Counterparty-provided strings in failure messages are no longer logged in full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714). * Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer cause us to allocate large amounts of memory (lightningdevkit#4712). Thanks to Project Loupe for reporting most of the issues fixed in this release. Conflicts resolved in: * lightning/src/chain/channelmonitor.rs * lightning/src/events/mod.rs * lightning/src/ln/channelmanager.rs * lightning/src/ln/mod.rs * lightning/src/ln/offers_tests.rs * lightning/src/ln/onion_utils.rs
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regenerate_and_broadcast_spend_if_necessaryusedpending_sweep: AtomicBoolas a single-runner gate but only cleared the flag with an unconditionalstore(false)after the inner future resolved. If the caller's future was dropped while the inner await wasPending— whichtokio::time::timeout,futures::select!, manualJoinHandle::abort, etc. all do — the reset never ran, leaving the flag stucktrueand every subsequent call to the function short-circuiting withOk(()).Because
OutputSweeperis what claimsSpendableOutputDescriptors back to the user's wallet after channel closure (including HTLC outputs with time-bounded recovery deadlines), a stuck flag turns into fund-loss exposure: time-sensitive HTLC sweeps simply stop happening, while every other code path keeps queueing new outputs to sweep, until the process is restarted.Replace the trailing
store(false)with an RAIIPendingSweepGuardwhoseDropimpl always releases the flag — covering normal return, error, and cancellation alike.Co-Authored-By: HAL 9000