diff --git a/src/bin_node/node_run_command.ml b/src/bin_node/node_run_command.ml
index 22caf3542..80f87c90d 100644
--- a/src/bin_node/node_run_command.ml
+++ b/src/bin_node/node_run_command.ml
@@ -93,7 +93,7 @@ let init_logger ?verbosity (log_config : Node_config_file.log) =
 let init_node ?sandbox (config : Node_config_file.t) =
   let patch_context json ctxt =
     let module Proto = (val Registred_protocol.get_exn genesis.protocol) in
-    Lwt_utils_unix.protect begin fun () ->
+    protect begin fun () ->
       Proto.configure_sandbox ctxt json
     end >|= function
     | Error err ->
diff --git a/src/lib_error_monad/error_monad.ml b/src/lib_error_monad/error_monad.ml
index e5dcf76b3..fd66f785a 100644
--- a/src/lib_error_monad/error_monad.ml
+++ b/src/lib_error_monad/error_monad.ml
@@ -474,12 +474,6 @@ module Make() = struct
     else
       Format.kasprintf (fun msg -> fail (Assert_error (loc, msg))) fmt
 
-
-  let protect ~on_error t =
-    t  >>= function
-    | Ok res -> return res
-    | Error err -> on_error err
-
 end
 
 include Make()
@@ -501,15 +495,6 @@ let record_trace_exn exn f = record_trace (Exn exn) f
 let failure fmt =
   Format.kasprintf (fun str -> Exn (Failure str)) fmt
 
-
-let protect ?on_error t =
-  Lwt.catch t (fun exn -> fail (Exn exn)) >>= function
-  | Ok res -> return res
-  | Error err ->
-      match on_error with
-      | Some f -> f err
-      | None -> Lwt.return (Error err)
-
 let pp_exn ppf exn = pp ppf (Exn exn)
 
 let () =
@@ -527,3 +512,49 @@ let () =
       | Exn exn -> Some (Printexc.to_string exn)
       | _ -> None)
     (fun msg -> Exn (Failure msg))
+
+type error += Canceled
+
+let protect ?on_error ?canceler t =
+  let cancelation =
+    match canceler with
+    | None -> Lwt_utils.never_ending
+    | Some canceler ->
+        (Lwt_canceler.cancelation canceler >>= fun () ->
+         fail Canceled ) in
+  let res =
+    Lwt.pick [ cancelation ;
+               Lwt.catch t (fun exn -> fail (Exn exn)) ] in
+  res >>= function
+  | Ok _ -> res
+  | Error err ->
+      let canceled =
+        Option.unopt_map canceler ~default:false ~f:Lwt_canceler.canceled in
+      let err = if canceled then [Canceled] else err in
+      match on_error with
+      | None -> Lwt.return (Error err)
+      | Some on_error ->
+          Lwt.catch (fun () -> on_error err) (fun exn -> fail (Exn exn))
+
+type error += Timeout
+
+let () =
+  register_error_kind
+    `Temporary
+    ~id:"utils.Timeout"
+    ~title:"Timeout"
+    ~description:"Timeout"
+    Data_encoding.unit
+    (function Timeout -> Some () | _ -> None)
+    (fun () -> Timeout)
+
+let with_timeout ?(canceler = Lwt_canceler.create ()) timeout f =
+  let target = f canceler in
+  Lwt.choose [ timeout ; (target >|= fun _ -> ()) ] >>= fun () ->
+  if Lwt.state target <> Lwt.Sleep then begin
+    Lwt.cancel timeout ;
+    target
+  end else begin
+    Lwt_canceler.cancel canceler >>= fun () ->
+    fail Timeout
+  end
diff --git a/src/lib_error_monad/error_monad.mli b/src/lib_error_monad/error_monad.mli
index 4ebc9c960..b344504c3 100644
--- a/src/lib_error_monad/error_monad.mli
+++ b/src/lib_error_monad/error_monad.mli
@@ -28,10 +28,6 @@ val failwith :
   ('a, Format.formatter, unit, 'b tzresult Lwt.t) format4 ->
   'a
 
-val protect :
-  ?on_error: (error list -> 'a tzresult Lwt.t) ->
-  (unit -> 'a tzresult Lwt.t) -> 'a tzresult Lwt.t
-
 val error_exn : exn -> 'a tzresult
 val record_trace_exn : exn -> 'a tzresult -> 'a tzresult
 val trace_exn : exn -> 'b tzresult Lwt.t -> 'b tzresult Lwt.t
@@ -45,6 +41,18 @@ val failure : ('a, Format.formatter, unit, error) format4 -> 'a
 type error += Exn of exn
 type error += Unclassified of string
 
+type error += Canceled
+
+val protect :
+  ?on_error:(error list -> 'a tzresult Lwt.t) ->
+  ?canceler:Lwt_canceler.t ->
+  (unit -> 'a tzresult Lwt.t) -> 'a tzresult Lwt.t
+
+type error += Timeout
+val with_timeout:
+  ?canceler:Lwt_canceler.t ->
+  unit Lwt.t -> (Lwt_canceler.t -> 'a tzresult Lwt.t) -> 'a tzresult Lwt.t
+
 module Make() : Error_monad_sig.S
 
 (**/**)
diff --git a/src/lib_error_monad/error_monad_sig.ml b/src/lib_error_monad/error_monad_sig.ml
index fff53379e..420fa03c8 100644
--- a/src/lib_error_monad/error_monad_sig.ml
+++ b/src/lib_error_monad/error_monad_sig.ml
@@ -109,10 +109,6 @@ module type S = sig
     bool -> string ->
     ('a, Format.formatter, unit, unit tzresult Lwt.t) format4 -> 'a
 
-  val protect :
-    on_error: (error list -> 'a tzresult Lwt.t) ->
-    'a tzresult Lwt.t -> 'a tzresult Lwt.t
-
   (** {2 In-monad list iterators} ********************************************)
 
   (** A {!List.iter} in the monad *)
diff --git a/src/lib_p2p/p2p_io_scheduler.ml b/src/lib_p2p/p2p_io_scheduler.ml
index 41d0d248f..eb316110e 100644
--- a/src/lib_p2p/p2p_io_scheduler.ml
+++ b/src/lib_p2p/p2p_io_scheduler.ml
@@ -120,7 +120,7 @@ module Scheduler(IO : IO) = struct
           false, (Queue.pop st.readys_low)
       in
       match msg with
-      | Error [ Lwt_utils_unix.Canceled ] ->
+      | Error [ Canceled ] ->
           worker_loop st
       | Error ([Connection_closed |
                 Exn ( Lwt_pipe.Closed |
@@ -140,7 +140,7 @@ module Scheduler(IO : IO) = struct
           conn.current_push <- begin
             IO.push conn.out_param msg >>= function
             | Ok ()
-            | Error [ Lwt_utils_unix.Canceled ] ->
+            | Error [ Canceled ] ->
                 return ()
             | Error ([Connection_closed |
                       Exn (Unix.Unix_error (EBADF, _, _) |
@@ -481,10 +481,10 @@ let close ?timeout conn =
     | None ->
         return (Lwt_canceler.cancelation conn.canceler)
     | Some timeout ->
-        Lwt_utils_unix.with_timeout
-          ~canceler:conn.canceler timeout begin fun canceler ->
-          return (Lwt_canceler.cancelation canceler)
-        end
+        with_timeout
+          ~canceler:conn.canceler
+          (Lwt_unix.sleep timeout)
+          (fun canceler -> return (Lwt_canceler.cancelation canceler))
   end >>=? fun _ ->
   conn.write_conn.current_push >>= fun res ->
   lwt_log_info "<-- close (%d)" conn.id >>= fun () ->
diff --git a/src/lib_p2p/p2p_maintenance.ml b/src/lib_p2p/p2p_maintenance.ml
index 95946b54c..bf56abe70 100644
--- a/src/lib_p2p/p2p_maintenance.ml
+++ b/src/lib_p2p/p2p_maintenance.ml
@@ -119,7 +119,7 @@ and too_few_connections st n_connected =
        discover the local network and then wait *)
     Option.iter ~f:P2p_discovery.restart st.disco ;
     P2p_pool.broadcast_bootstrap_msg pool ;
-    Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+    protect ~canceler:st.canceler begin fun () ->
       Lwt.pick [
         P2p_pool.Pool_event.wait_new_peer pool ;
         Lwt_unix.sleep 5.0 (* TODO exponential back-off ??
@@ -146,7 +146,7 @@ and too_many_connections st n_connected =
 let rec worker_loop st =
   let Pool pool = st.pool in
   begin
-    Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+    protect ~canceler:st.canceler begin fun () ->
       Lwt.pick [
         Lwt_unix.sleep 120. ; (* every two minutes *)
         Lwt_condition.wait st.please_maintain ; (* when asked *)
@@ -165,7 +165,7 @@ let rec worker_loop st =
     end
   end >>= function
   | Ok () -> worker_loop st
-  | Error [ Lwt_utils_unix.Canceled ] -> Lwt.return_unit
+  | Error [ Canceled ] -> Lwt.return_unit
   | Error _ -> Lwt.return_unit
 
 let run ~connection_timeout bounds pool disco =
diff --git a/src/lib_p2p/p2p_pool.ml b/src/lib_p2p/p2p_pool.ml
index 9a880324e..13bca7333 100644
--- a/src/lib_p2p/p2p_pool.ml
+++ b/src/lib_p2p/p2p_pool.ml
@@ -87,7 +87,7 @@ module Answerer = struct
 
   let rec worker_loop st =
     Lwt_unix.yield () >>= fun () ->
-    Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+    protect ~canceler:st.canceler begin fun () ->
       P2p_socket.read st.conn
     end >>= function
     | Ok (_, Bootstrap) -> begin
@@ -122,7 +122,7 @@ module Answerer = struct
         (* TODO: Penalize peer... *)
         Lwt_canceler.cancel st.canceler >>= fun () ->
         Lwt.return_unit
-    | Error [Lwt_utils_unix.Canceled] ->
+    | Error [ Canceled ] ->
         Lwt.return_unit
     | Error err ->
         lwt_log_error "@[Answerer unexpected error:@ %a@]"
@@ -568,7 +568,7 @@ let rec connect ~timeout pool point =
     (active_connections pool <= pool.config.max_connections)
     Too_many_connections >>=? fun () ->
   let canceler = Lwt_canceler.create () in
-  Lwt_utils_unix.with_timeout ~canceler timeout begin fun canceler ->
+  with_timeout ~canceler (Lwt_unix.sleep timeout) begin fun canceler ->
     let point_info =
       register_point pool pool.config.identity.peer_id point in
     let addr, port as point = P2p_point_state.Info.point point_info in
@@ -581,7 +581,7 @@ let rec connect ~timeout pool point =
     let uaddr =
       Lwt_unix.ADDR_INET (Ipaddr_unix.V6.to_inet_addr addr, port) in
     lwt_debug "connect: %a" P2p_point.Id.pp point >>= fun () ->
-    Lwt_utils_unix.protect ~canceler begin fun () ->
+    protect ~canceler begin fun () ->
       log pool (Outgoing_connection point) ;
       Lwt_unix.connect fd uaddr >>= fun () ->
       return ()
@@ -603,7 +603,7 @@ and authenticate pool ?point_info canceler fd point =
   lwt_debug "authenticate: %a%s"
     P2p_point.Id.pp point
     (if incoming then " incoming" else "") >>= fun () ->
-  Lwt_utils_unix.protect ~canceler begin fun () ->
+  protect ~canceler begin fun () ->
     P2p_socket.authenticate
       ~proof_of_work_target:pool.config.proof_of_work_target
       ~incoming (P2p_io_scheduler.register pool.io_sched fd) point
@@ -612,7 +612,7 @@ and authenticate pool ?point_info canceler fd point =
   end ~on_error: begin fun err ->
     (* TODO do something when the error is Not_enough_proof_of_work ?? *)
     begin match err with
-      | [ Lwt_utils_unix.Canceled ] ->
+      | [ Canceled ] ->
           (* Currently only on time out *)
           lwt_debug "authenticate: %a%s -> canceled"
             P2p_point.Id.pp point
@@ -682,7 +682,7 @@ and authenticate pool ?point_info canceler fd point =
       lwt_debug "authenticate: %a -> accept %a"
         P2p_point.Id.pp point
         P2p_connection.Info.pp info >>= fun () ->
-      Lwt_utils_unix.protect ~canceler begin fun () ->
+      protect ~canceler begin fun () ->
         P2p_socket.accept
           ?incoming_message_queue_size:pool.config.incoming_message_queue_size
           ?outgoing_message_queue_size:pool.config.outgoing_message_queue_size
@@ -881,7 +881,7 @@ and swap pool conn current_peer_id new_point =
       pool.latest_accepted_swap <- pool.latest_succesfull_swap ;
       log pool (Swap_failure { source = source_peer_id }) ;
       match err with
-      | [ Lwt_utils_unix.Timeout ] ->
+      | [ Timeout ] ->
           lwt_debug "Swap to %a was interupted: %a"
             P2p_point.Id.pp new_point pp_print_error err
       | _ ->
@@ -898,8 +898,8 @@ let accept pool fd point =
     let canceler = Lwt_canceler.create () in
     P2p_point.Table.add pool.incoming point canceler ;
     Lwt.async begin fun () ->
-      Lwt_utils_unix.with_timeout
-        ~canceler pool.config.authentification_timeout
+      with_timeout
+        ~canceler (Lwt_unix.sleep pool.config.authentification_timeout)
         (fun canceler -> authenticate pool canceler fd point)
     end
 
diff --git a/src/lib_p2p/p2p_socket.ml b/src/lib_p2p/p2p_socket.ml
index f6fa85bd3..bde328077 100644
--- a/src/lib_p2p/p2p_socket.ml
+++ b/src/lib_p2p/p2p_socket.ml
@@ -249,7 +249,7 @@ module Reader = struct
           lwt_debug "[read_message] incremental decoding error" >>= fun () ->
           return None
       | Await decode_next_buf ->
-          Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+          protect ~canceler:st.canceler begin fun () ->
             Crypto.read_chunk st.conn.fd st.conn.cryptobox_data
           end >>=? fun buf ->
           lwt_debug
@@ -265,12 +265,12 @@ module Reader = struct
       read_message st init_mbytes >>=? fun msg ->
       match msg with
       | None ->
-          Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+          protect ~canceler:st.canceler begin fun () ->
             Lwt_pipe.push st.messages (Error [Decoding_error]) >>= fun () ->
             return None
           end
       | Some (msg, size, rem_mbytes) ->
-          Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+          protect ~canceler:st.canceler begin fun () ->
             Lwt_pipe.push st.messages (Ok (size, msg)) >>= fun () ->
             return (Some rem_mbytes)
           end
@@ -280,7 +280,7 @@ module Reader = struct
     | Ok None ->
         Lwt_canceler.cancel st.canceler >>= fun () ->
         Lwt.return_unit
-    | Error [Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed] ->
+    | Error [Canceled | Exn Lwt_pipe.Closed] ->
         lwt_debug "connection closed to %a"
           P2p_connection.Info.pp st.conn.info >>= fun () ->
         Lwt.return_unit
@@ -331,7 +331,7 @@ module Writer = struct
     let rec loop = function
       | [] -> return ()
       | buf :: l ->
-          Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+          protect ~canceler:st.canceler begin fun () ->
             Crypto.write_chunk st.conn.fd st.conn.cryptobox_data buf
           end >>=? fun () ->
           lwt_debug "writing %d bytes to %a"
@@ -345,10 +345,10 @@ module Writer = struct
 
   let rec worker_loop st =
     Lwt_unix.yield () >>= fun () ->
-    Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+    protect ~canceler:st.canceler begin fun () ->
       Lwt_pipe.pop st.messages >>= return
     end >>= function
-    | Error [Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed] ->
+    | Error [Canceled | Exn Lwt_pipe.Closed] ->
         lwt_debug "connection closed to %a"
           P2p_connection.Info.pp st.conn.info >>= fun () ->
         Lwt.return_unit
@@ -370,7 +370,7 @@ module Writer = struct
                   Lwt.wakeup_later u
                     (Error [P2p_io_scheduler.Connection_closed])) ;
             match err with
-            | [ Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed ] ->
+            | [ Canceled | Exn Lwt_pipe.Closed ] ->
                 lwt_debug "connection closed to %a"
                   P2p_connection.Info.pp st.conn.info >>= fun () ->
                 Lwt.return_unit
@@ -453,7 +453,7 @@ let info { conn } = conn.info
 let accept
     ?incoming_message_queue_size ?outgoing_message_queue_size
     ?binary_chunks_size (fd, info, cryptobox_data) encoding =
-  Lwt_utils_unix.protect begin fun () ->
+  protect begin fun () ->
     Ack.write fd cryptobox_data Ack >>=? fun () ->
     Ack.read fd cryptobox_data
   end ~on_error:begin fun err ->
diff --git a/src/lib_p2p/p2p_welcome.ml b/src/lib_p2p/p2p_welcome.ml
index a0b541591..213b7c9e6 100644
--- a/src/lib_p2p/p2p_welcome.ml
+++ b/src/lib_p2p/p2p_welcome.ml
@@ -21,7 +21,7 @@ type t = {
 let rec worker_loop st =
   let Pool pool = st.pool in
   Lwt_unix.yield () >>= fun () ->
-  Lwt_utils_unix.protect ~canceler:st.canceler begin fun () ->
+  protect ~canceler:st.canceler begin fun () ->
     Lwt_unix.accept st.socket >>= return
   end >>= function
   | Ok (fd, addr) ->
@@ -32,7 +32,7 @@ let rec worker_loop st =
             (Ipaddr_unix.V6.of_inet_addr_exn addr, port) in
       P2p_pool.accept pool fd point ;
       worker_loop st
-  | Error [Lwt_utils_unix.Canceled] ->
+  | Error [ Canceled ] ->
       Lwt.return_unit
   | Error err ->
       lwt_log_error "@[<v 2>Unexpected error in the Welcome worker@ %a@]"
diff --git a/src/lib_p2p/test/test_p2p_pool.ml b/src/lib_p2p/test/test_p2p_pool.ml
index b9ff90c0d..382ce61da 100644
--- a/src/lib_p2p/test/test_p2p_pool.ml
+++ b/src/lib_p2p/test/test_p2p_pool.ml
@@ -122,8 +122,8 @@ module Simple = struct
     | Error ([ P2p_pool.Connection_refused
              | P2p_pool.Pending_connection
              | P2p_socket.Rejected
-             | Lwt_utils_unix.Canceled
-             | Lwt_utils_unix.Timeout
+             | Canceled
+             | Timeout
              | P2p_pool.Rejected _ as err ]) ->
         lwt_log_info "Connection to %a failed (%a)"
           P2p_point.Id.pp point
@@ -134,9 +134,9 @@ module Simple = struct
                  Format.fprintf ppf "pending connection"
              | P2p_socket.Rejected ->
                  Format.fprintf ppf "rejected"
-             | Lwt_utils_unix.Canceled ->
+             | Canceled ->
                  Format.fprintf ppf "canceled"
-             | Lwt_utils_unix.Timeout ->
+             | Timeout ->
                  Format.fprintf ppf "timeout"
              | P2p_pool.Rejected peer ->
                  Format.fprintf ppf "rejected (%a)" P2p_peer.Id.pp peer
diff --git a/src/lib_shell/block_validator.ml b/src/lib_shell/block_validator.ml
index 268b1f5ad..f7086c575 100644
--- a/src/lib_shell/block_validator.ml
+++ b/src/lib_shell/block_validator.ml
@@ -241,7 +241,7 @@ let on_request
                 net_state header.shell.predecessor >>=? fun pred ->
               get_proto pred hash >>=? fun proto ->
               (* TODO also protect with [Worker.canceler w]. *)
-              Lwt_utils_unix.protect ?canceler begin fun () ->
+              protect ?canceler begin fun () ->
                 apply_block
                   (Distributed_db.net_state net_db)
                   pred proto hash header operations
@@ -264,7 +264,7 @@ let on_request
               end
             (* TODO catch other temporary error (e.g. system errors)
                and do not 'commit' them on disk... *)
-            | Error [Lwt_utils_unix.Canceled | Unavailable_protocol _] as err ->
+            | Error [Canceled | Unavailable_protocol _] as err ->
                 return err
             | Error errors ->
                 Worker.protect w begin fun () ->
diff --git a/src/lib_shell/bootstrap_pipeline.ml b/src/lib_shell/bootstrap_pipeline.ml
index 215a2bad0..891ff8672 100644
--- a/src/lib_shell/bootstrap_pipeline.ml
+++ b/src/lib_shell/bootstrap_pipeline.ml
@@ -55,7 +55,7 @@ let fetch_step pipeline (step : Block_locator_iterator.step)  =
       lwt_debug "fetching block header %a from peer %a."
         Block_hash.pp_short hash
         P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
-      Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+      protect ~canceler:pipeline.canceler begin fun () ->
         Distributed_db.Block_header.fetch
           ~timeout:pipeline.block_header_timeout
           pipeline.net_db ~peer:pipeline.peer_id
@@ -69,7 +69,7 @@ let fetch_step pipeline (step : Block_locator_iterator.step)  =
   fetch_loop [] step.block step.step >>=? fun headers ->
   iter_s
     begin fun header ->
-      Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+      protect ~canceler:pipeline.canceler begin fun () ->
         Lwt_pipe.push pipeline.fetched_headers header >>= return
       end
     end
@@ -87,7 +87,7 @@ let headers_fetch_worker_loop pipeline =
         P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
       Lwt_pipe.close pipeline.fetched_headers ;
       Lwt.return_unit
-  | Error [Exn Lwt.Canceled | Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed] ->
+  | Error [Exn Lwt.Canceled | Canceled | Exn Lwt_pipe.Closed] ->
       Lwt.return_unit
   | Error [ Distributed_db.Block_header.Timeout bh ] ->
       lwt_log_info "request for header %a from peer %a timed out."
@@ -105,7 +105,7 @@ let headers_fetch_worker_loop pipeline =
 let rec operations_fetch_worker_loop pipeline =
   begin
     Lwt_unix.yield () >>= fun () ->
-    Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+    protect ~canceler:pipeline.canceler begin fun () ->
       Lwt_pipe.pop pipeline.fetched_headers >>= return
     end >>=? fun (hash, header) ->
     lwt_log_info "fetching operations of block %a from peer %a."
@@ -113,7 +113,7 @@ let rec operations_fetch_worker_loop pipeline =
       P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
     map_p
       (fun i ->
-         Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+         protect ~canceler:pipeline.canceler begin fun () ->
            Distributed_db.Operations.fetch
              ~timeout:pipeline.block_operations_timeout
              pipeline.net_db ~peer:pipeline.peer_id
@@ -123,14 +123,14 @@ let rec operations_fetch_worker_loop pipeline =
     lwt_log_info "fetched operations of block %a from peer %a."
       Block_hash.pp_short hash
       P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
-    Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+    protect ~canceler:pipeline.canceler begin fun () ->
       Lwt_pipe.push pipeline.fetched_blocks
         (hash, header, operations) >>= return
     end
   end >>= function
   | Ok () ->
       operations_fetch_worker_loop pipeline
-  | Error [Exn Lwt.Canceled | Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed] ->
+  | Error [Exn Lwt.Canceled | Canceled | Exn Lwt_pipe.Closed] ->
       Lwt_pipe.close pipeline.fetched_blocks ;
       Lwt.return_unit
   | Error [ Distributed_db.Operations.Timeout (bh, n) ] ->
@@ -149,13 +149,13 @@ let rec operations_fetch_worker_loop pipeline =
 let rec validation_worker_loop pipeline =
   begin
     Lwt_unix.yield () >>= fun () ->
-    Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+    protect ~canceler:pipeline.canceler begin fun () ->
       Lwt_pipe.pop pipeline.fetched_blocks >>= return
     end >>=? fun (hash, header, operations) ->
     lwt_log_info "requesting validation for block %a from peer %a."
       Block_hash.pp_short hash
       P2p_peer.Id.pp_short pipeline.peer_id >>= fun () ->
-    Lwt_utils_unix.protect ~canceler:pipeline.canceler begin fun () ->
+    protect ~canceler:pipeline.canceler begin fun () ->
       Block_validator.validate
         ~canceler:pipeline.canceler
         ~notify_new_block:pipeline.notify_new_block
@@ -168,7 +168,7 @@ let rec validation_worker_loop pipeline =
     return ()
   end >>= function
   | Ok () -> validation_worker_loop pipeline
-  | Error [Exn Lwt.Canceled | Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed] ->
+  | Error [Exn Lwt.Canceled | Canceled | Exn Lwt_pipe.Closed] ->
       Lwt.return_unit
   | Error ([ Block_validator_errors.Invalid_block _
            | Block_validator_errors.Unavailable_protocol _ ] as err ) ->
diff --git a/src/lib_shell/distributed_db.ml b/src/lib_shell/distributed_db.ml
index d406e00d4..d312cca04 100644
--- a/src/lib_shell/distributed_db.ml
+++ b/src/lib_shell/distributed_db.ml
@@ -629,7 +629,7 @@ module P2p_reader = struct
       end
 
   let rec worker_loop global_db state =
-    Lwt_utils_unix.protect ~canceler:state.canceler begin fun () ->
+    protect ~canceler:state.canceler begin fun () ->
       P2p.recv global_db.p2p state.conn
     end >>= function
     | Ok msg ->
diff --git a/src/lib_shell/protocol_validator.ml b/src/lib_shell/protocol_validator.ml
index 9fbb78cd7..2bddd9181 100644
--- a/src/lib_shell/protocol_validator.ml
+++ b/src/lib_shell/protocol_validator.ml
@@ -78,7 +78,7 @@ let () =
 
 let rec worker_loop bv =
   begin
-    Lwt_utils_unix.protect ~canceler:bv.canceler begin fun () ->
+    protect ~canceler:bv.canceler begin fun () ->
       Lwt_pipe.pop bv.messages >>= return
     end >>=? function Message (request, wakener) ->
     match request with
@@ -115,7 +115,7 @@ let rec worker_loop bv =
   end >>= function
   | Ok () ->
       worker_loop bv
-  | Error [Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed] ->
+  | Error [Canceled | Exn Lwt_pipe.Closed] ->
       lwt_log_notice "terminating" >>= fun () ->
       Lwt.return_unit
   | Error err ->
diff --git a/src/lib_shell/worker.ml b/src/lib_shell/worker.ml
index 85f176565..73fb2bf87 100644
--- a/src/lib_shell/worker.ml
+++ b/src/lib_shell/worker.ml
@@ -203,9 +203,6 @@ module Make
   let trigger_shutdown w =
     Lwt.ignore_result (Lwt_canceler.cancel w.canceler)
 
-  let protect { canceler } ?on_error f =
-    Lwt_utils_unix.protect ?on_error ~canceler f
-
   let canceler { canceler } = canceler
 
   let log_event w evt =
@@ -272,7 +269,7 @@ module Make
       Lwt.return_unit in
     let rec loop () =
       begin
-        Lwt_utils_unix.protect ~canceler:w.canceler begin fun () ->
+        protect ~canceler:w.canceler begin fun () ->
           pop w
         end >>=? function
         | None -> Handlers.on_no_request w
@@ -303,7 +300,7 @@ module Make
       end >>= function
       | Ok () ->
           loop ()
-      | Error [Lwt_utils_unix.Canceled | Exn Lwt_pipe.Closed | Exn Lwt_dropbox.Closed ] ->
+      | Error [Canceled | Exn Lwt_pipe.Closed | Exn Lwt_dropbox.Closed ] ->
           Logger.lwt_log_info
             "[%a] worker terminated"
             Name.pp w.name >>= fun () ->
@@ -413,4 +410,7 @@ module Make
       (fun n w acc -> (n, w) :: acc)
       instances []
 
+  let protect { canceler } ?on_error f =
+    protect ?on_error ~canceler f
+
 end
diff --git a/src/lib_stdlib_lwt/lwt_lock_file.ml b/src/lib_stdlib_lwt/lwt_lock_file.ml
index 7f86b50b7..df0999d39 100644
--- a/src/lib_stdlib_lwt/lwt_lock_file.ml
+++ b/src/lib_stdlib_lwt/lwt_lock_file.ml
@@ -34,7 +34,7 @@ let blocking_create
     create_inner Unix.F_LOCK ~close_on_exec ~unlink_on_exit fn in
   match timeout with
   | None -> create ()
-  | Some duration -> Lwt_utils_unix.with_timeout duration (fun _ -> create ())
+  | Some duration -> with_timeout (Lwt_unix.sleep duration) (fun _ -> create ())
 
 let is_locked fn =
   if not @@ Sys.file_exists fn then return false else
@@ -50,7 +50,7 @@ let is_locked fn =
 
 let get_pid fn =
   let open Lwt_io in
-  Lwt_utils_unix.protect begin fun () ->
+  protect begin fun () ->
     with_file ~mode:Input fn begin fun ic ->
       read ic >>= fun content ->
       return (int_of_string content)
diff --git a/src/lib_stdlib_lwt/lwt_utils_unix.ml b/src/lib_stdlib_lwt/lwt_utils_unix.ml
index 4cb7fc468..235c7f222 100644
--- a/src/lib_stdlib_lwt/lwt_utils_unix.ml
+++ b/src/lib_stdlib_lwt/lwt_utils_unix.ml
@@ -116,53 +116,3 @@ let getaddrinfo ~passive ~node ~service =
       (fun { ai_addr ; _ } -> of_sockaddr ai_addr)
       addr in
   Lwt.return points
-
-open Error_monad
-
-type error += Canceled
-
-let protect ?on_error ?canceler t =
-  let cancelation =
-    match canceler with
-    | None -> Lwt_utils.never_ending
-    | Some canceler ->
-        (Lwt_canceler.cancelation canceler >>= fun () ->
-         fail Canceled ) in
-  let res =
-    Lwt.pick [ cancelation ;
-               Lwt.catch t (fun exn -> fail (Exn exn)) ] in
-  res >>= function
-  | Ok _ -> res
-  | Error err ->
-      let canceled =
-        Option.unopt_map canceler ~default:false ~f:Lwt_canceler.canceled in
-      let err = if canceled then [Canceled] else err in
-      match on_error with
-      | None -> Lwt.return (Error err)
-      | Some on_error ->
-          Lwt.catch (fun () -> on_error err) (fun exn -> fail (Exn exn))
-
-type error += Timeout
-
-let () =
-  register_error_kind
-    `Temporary
-    ~id:"utils.Timeout"
-    ~title:"Timeout"
-    ~description:"Timeout"
-    Data_encoding.unit
-    (function Timeout -> Some () | _ -> None)
-    (fun () -> Timeout)
-
-let with_timeout ?(canceler = Lwt_canceler.create ()) timeout f =
-  let timeout = Lwt_unix.sleep timeout in
-  let target = f canceler in
-  Lwt.choose [ timeout ; (target >|= fun _ -> ()) ] >>= fun () ->
-  Lwt_unix.yield () >>= fun () ->
-  if Lwt.state target <> Lwt.Sleep then begin
-    Lwt.cancel timeout ;
-    target
-  end else begin
-    Lwt_canceler.cancel canceler >>= fun () ->
-    fail Timeout
-  end
diff --git a/src/lib_stdlib_lwt/lwt_utils_unix.mli b/src/lib_stdlib_lwt/lwt_utils_unix.mli
index 7fc566739..ec5143e4e 100644
--- a/src/lib_stdlib_lwt/lwt_utils_unix.mli
+++ b/src/lib_stdlib_lwt/lwt_utils_unix.mli
@@ -28,18 +28,3 @@ val getaddrinfo:
   passive:bool ->
   node:string -> service:string ->
   (Ipaddr.V6.t * int) list Lwt.t
-
-open Error_monad
-
-type error += Canceled
-
-val protect :
-  ?on_error:(error list -> 'a tzresult Lwt.t) ->
-  ?canceler:Lwt_canceler.t ->
-  (unit -> 'a tzresult Lwt.t) -> 'a tzresult Lwt.t
-
-type error += Timeout
-val with_timeout:
-  ?canceler:Lwt_canceler.t ->
-  float -> (Lwt_canceler.t -> 'a tzresult Lwt.t) -> 'a tzresult Lwt.t
-