Drop skip too large condition for liveness safety (#6014)

* Drop skip too large condition for liveness safety

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -114,7 +114,7 @@ use std::collections::HashSet;
 use std::io::prelude::*;
 use std::marker::PhantomData;
 use std::sync::Arc;
-use std::time::{Duration, Instant};
+use std::time::Duration;
 use store::iter::{BlockRootsIterator, ParentRootBlockIterator, StateRootsIterator};
 use store::{
     DatabaseBlock, Error as DBError, HotColdDB, KeyValueStore, KeyValueStoreOp, StoreItem, StoreOp,
@@ -1410,10 +1410,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                     )
                 }
 
-                let start_slot = head_state.slot();
-                let task_start = Instant::now();
-                let max_task_runtime = Duration::from_secs(self.spec.seconds_per_slot);
-
                 let head_state_slot = head_state.slot();
                 let mut state = head_state;
 
@@ -1423,18 +1419,6 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 };
 
                 while state.slot() < slot {
-                    // Do not allow and forward state skip that takes longer than the maximum task duration.
-                    //
-                    // This is a protection against nodes doing too much work when they're not synced
-                    // to a chain.
-                    if task_start + max_task_runtime < Instant::now() {
-                        return Err(Error::StateSkipTooLarge {
-                            start_slot,
-                            requested_slot: slot,
-                            max_task_runtime,
-                        });
-                    }
-
                     // Note: supplying some `state_root` when it is known would be a cheap and easy
                     // optimization.
                     match per_slot_processing(&mut state, skip_state_root, &self.spec) {

beacon_node/beacon_chain/src/errors.rs

@@ -28,7 +28,6 @@ use state_processing::{
     state_advance::Error as StateAdvanceError,
     BlockProcessingError, BlockReplayError, EpochProcessingError, SlotProcessingError,
 };
-use std::time::Duration;
 use task_executor::ShutdownReason;
 use tokio::task::JoinError;
 use types::milhouse::Error as MilhouseError;
@@ -77,11 +76,6 @@ pub enum BeaconChainError {
     ProposerSlashingValidationError(ProposerSlashingValidationError),
     AttesterSlashingValidationError(AttesterSlashingValidationError),
     BlsExecutionChangeValidationError(BlsExecutionChangeValidationError),
-    StateSkipTooLarge {
-        start_slot: Slot,
-        requested_slot: Slot,
-        max_task_runtime: Duration,
-    },
     MissingFinalizedStateRoot(Slot),
     /// Returned when an internal check fails, indicating corrupt data.
     InvariantViolated(String),