Merge pull request #5737 from edwintorok/private/edvint/taskbugfix

CA-394882,CA-394883: Fix task server race condition, and testcase race condition

Author: edwintorok

ocaml/xapi-idl/lib/task_server.ml

@@ -112,10 +112,8 @@ functor
 
     (* [next_task_id ()] returns a fresh task id *)
     let next_task_id =
-      let counter = ref 0 in
-      fun () ->
-        let result = string_of_int !counter in
-        incr counter ; result
+      let counter = Atomic.make 0 in
+      fun () -> Atomic.fetch_and_add counter 1 |> string_of_int
 
     let set_cancel_trigger tasks dbg n =
       with_lock tasks.m (fun () -> tasks.test_cancel_trigger <- Some (dbg, n))

ocaml/xenopsd/test/test.ml

@@ -91,7 +91,9 @@ let wait_for_tasks id =
     List.iter
       (function
         | Dynamic.Task id' ->
-            if task_ended dbg id' then ids := StringSet.remove id' !ids
+            (* ignore events on tasks that are not ours, they may have been deleted *)
+            if StringSet.mem id' !ids && task_ended dbg id' then
+              ids := StringSet.remove id' !ids
         | _ ->
             ()
         )
@@ -100,6 +102,7 @@ let wait_for_tasks id =
 
 let success_task id =
   let t = Client.TASK.stat dbg id in
+  D.debug "%s: destroying task %s" __FUNCTION__ id ;
   Client.TASK.destroy dbg id ;
   match t.Task.state with
   | Task.Completed _ ->
@@ -119,6 +122,7 @@ let success_task id =
 
 let fail_not_built_task id =
   let t = Client.TASK.stat dbg id in
+  D.debug "%s: destroying task %s" __FUNCTION__ id ;
   Client.TASK.destroy dbg id ;
   match t.Task.state with
   | Task.Completed _ ->
@@ -140,6 +144,7 @@ let fail_not_built_task id =
 
 let fail_invalid_vcpus_task id =
   let t = Client.TASK.stat dbg id in
+  D.debug "%s: destroying task %s" __FUNCTION__ id ;
   Client.TASK.destroy dbg id ;
   match t.Task.state with
   | Task.Completed _ ->
@@ -515,6 +520,7 @@ let vm_test_parallel_start_shutdown _ =
   ) ;
   let t = Unix.gettimeofday () in
   let tasks = List.map (fun id -> Client.VM.start dbg id false) ids in
+  D.debug "Waiting for tasks: %s" (String.concat ", " tasks) ;
   wait_for_tasks tasks ;
   if !verbose_timings then (
     Printf.fprintf stderr "Cleaning up tasks\n" ;