diff --git a/beacon_chain/gossip_processing/block_processor.nim b/beacon_chain/gossip_processing/block_processor.nim
index 53dd088e81..3cc34f1929 100644
--- a/beacon_chain/gossip_processing/block_processor.nim
+++ b/beacon_chain/gossip_processing/block_processor.nim
@@ -61,7 +61,7 @@ type
     blobs*: Opt[BlobSidecars]
     maybeFinalized*: bool
       ## The block source claims the block has been finalized already
-    resfut*: Future[Result[void, VerifierError]]
+    resfut*: Future[Result[void, VerifierError]].Raising([CancelledError])
     queueTick*: Moment # Moment when block was enqueued
     validationDur*: Duration # Time it took to perform gossip validation
     src*: MsgSource
@@ -385,7 +385,7 @@ proc checkBloblessSignature(self: BlockProcessor,
 proc enqueueBlock*(
     self: var BlockProcessor, src: MsgSource, blck: ForkedSignedBeaconBlock,
     blobs: Opt[BlobSidecars],
-    resfut: Future[Result[void, VerifierError]] = nil,
+    resfut: Future[Result[void, VerifierError]].Raising([CancelledError]) = nil,
     maybeFinalized = false,
     validationDur = Duration()) =
   withBlck(blck):
@@ -756,7 +756,7 @@ proc storeBlock(
 proc addBlock*(
     self: var BlockProcessor, src: MsgSource, blck: ForkedSignedBeaconBlock,
     blobs: Opt[BlobSidecars], maybeFinalized = false,
-    validationDur = Duration()): Future[Result[void, VerifierError]] =
+    validationDur = Duration()): Future[Result[void, VerifierError]] {.async: (raises: [CancelledError], raw: true).} =
   ## Enqueue a Gossip-validated block for consensus verification
   # Backpressure:
   #   There is no backpressure here - producers must wait for `resfut` to
diff --git a/beacon_chain/networking/peer_pool.nim b/beacon_chain/networking/peer_pool.nim
index 6bedebb892..cc21f05e1a 100644
--- a/beacon_chain/networking/peer_pool.nim
+++ b/beacon_chain/networking/peer_pool.nim
@@ -108,12 +108,15 @@ template outgoingEvent(eventType: EventType): AsyncEvent =
     pool.outNotFullEvent
 
 proc waitForEvent[A, B](pool: PeerPool[A, B], eventType: EventType,
-                        filter: set[PeerType]) {.async.} =
+                        filter: set[PeerType]) {.async: (raises: [CancelledError]).} =
   if filter == {PeerType.Incoming, PeerType.Outgoing} or filter == {}:
     var fut1 = incomingEvent(eventType).wait()
     var fut2 = outgoingEvent(eventType).wait()
     try:
-      discard await one(fut1, fut2)
+      try:
+        discard await one(fut1, fut2)
+      except ValueError:
+        raiseAssert "one precondition satisfied"
       if fut1.finished():
         if not(fut2.finished()):
           await fut2.cancelAndWait()
@@ -138,11 +141,11 @@ proc waitForEvent[A, B](pool: PeerPool[A, B], eventType: EventType,
     outgoingEvent(eventType).clear()
 
 proc waitNotEmptyEvent[A, B](pool: PeerPool[A, B],
-                             filter: set[PeerType]): Future[void] =
+                             filter: set[PeerType]) {.async: (raises: [CancelledError], raw: true).} =
   pool.waitForEvent(EventType.NotEmptyEvent, filter)
 
 proc waitNotFullEvent[A, B](pool: PeerPool[A, B],
-                            filter: set[PeerType]): Future[void] =
+                            filter: set[PeerType]){.async: (raises: [CancelledError], raw: true).} =
   pool.waitForEvent(EventType.NotFullEvent, filter)
 
 proc newPeerPool*[A, B](maxPeers = -1, maxIncomingPeers = -1,
@@ -451,7 +454,7 @@ proc getPeerSpaceMask[A, B](pool: PeerPool[A, B],
       {PeerType.Outgoing}
 
 proc waitForEmptySpace*[A, B](pool: PeerPool[A, B],
-                              peerType: PeerType) {.async.} =
+                              peerType: PeerType) {.async: (raises: [CancelledError]).} =
   ## This procedure will block until ``pool`` will have an empty space for peer
   ## of type ``peerType``.
   let mask = pool.getPeerSpaceMask(peerType)
@@ -459,7 +462,7 @@ proc waitForEmptySpace*[A, B](pool: PeerPool[A, B],
     await pool.waitNotFullEvent(mask)
 
 proc addPeer*[A, B](pool: PeerPool[A, B],
-                    peer: A, peerType: PeerType): Future[PeerStatus] {.async.} =
+                    peer: A, peerType: PeerType): Future[PeerStatus] {.async: (raises: [CancelledError]).} =
   ## Add peer ``peer`` of type ``peerType`` to PeerPool ``pool``.
   ##
   ## This procedure will wait for an empty space in PeerPool ``pool``, if
@@ -533,7 +536,7 @@ proc acquireItemImpl[A, B](pool: PeerPool[A, B],
 
 proc acquire*[A, B](pool: PeerPool[A, B],
                     filter = {PeerType.Incoming,
-                              PeerType.Outgoing}): Future[A] {.async.} =
+                              PeerType.Outgoing}): Future[A] {.async: (raises: [CancelledError]).} =
   ## Acquire peer from PeerPool ``pool``, which match the filter ``filter``.
   mixin getKey
   doAssert(filter != {}, "Filter must not be empty")
@@ -586,7 +589,7 @@ proc release*[A, B](pool: PeerPool[A, B], peers: openArray[A]) {.inline.} =
 proc acquire*[A, B](pool: PeerPool[A, B],
                     number: int,
                     filter = {PeerType.Incoming,
-                              PeerType.Outgoing}): Future[seq[A]] {.async.} =
+                              PeerType.Outgoing}): Future[seq[A]] {.async: (raises: [CancelledError]).} =
   ## Acquire ``number`` number of peers from PeerPool ``pool``, which match the
   ## filter ``filter``.
   doAssert(filter != {}, "Filter must not be empty")
@@ -735,7 +738,7 @@ proc clear*[A, B](pool: PeerPool[A, B]) =
   pool.acqIncPeersCount = 0
   pool.acqOutPeersCount = 0
 
-proc clearSafe*[A, B](pool: PeerPool[A, B]) {.async.} =
+proc clearSafe*[A, B](pool: PeerPool[A, B]) {.async: (raises: [CancelledError]).} =
   ## Performs "safe" clear. Safe means that it first acquires all the peers
   ## in PeerPool, and only after that it will reset storage.
   var acquired = newSeq[A]()