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fix: claim state_sync_requested with compare_exchange #3891

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fix: claim state_sync_requested with compare_exchange #3891

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11 changes: 8 additions & 3 deletions p2p/src/protocol.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -289,12 +289,17 @@ impl MessageHandler for Protocol {
);
return Err(Error::BadMessage);
}
if !self.state_sync_requested.load(Ordering::Relaxed) {
// Atomically claim the outstanding state-sync request so two
// concurrent archive messages cannot both observe "requested"
// and proceed (load+store race; see #3588).
if self
.state_sync_requested
.compare_exchange(true, false, Ordering::SeqCst, Ordering::Relaxed)

@wiesche89 wiesche89 Jul 11, 2026

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Issue #3588 raised a static analysis concern about another thread updating the flag between the load and store. The race described in this PR does not appear reachable, since archive responses from a peer are processed one at a time. Could we clarify which concrete interleaving this fixes? If it is a delayed response overlapping a newer request, this boolean still cannot tell them apart.

.is_err()
{
error!("handle_payload: txhashset archive received but from the wrong peer",);
return Err(Error::BadMessage);
}
// Update the sync state requested status
self.state_sync_requested.store(false, Ordering::Relaxed);

let start_time = Utc::now();
self.adapter
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