Make sleep(n) and Timer creation more MT-safe (#32174)

fixes #32152

base/asyncevent.jl

@@ -87,21 +87,11 @@ mutable struct Timer
         interval ≥ 0 || throw(ArgumentError("timer cannot have negative repeat interval of $interval seconds"))
 
         this = new(Libc.malloc(_sizeof_uv_timer), ThreadSynchronizer(), true)
-        err = ccall(:uv_timer_init, Cint, (Ptr{Cvoid}, Ptr{Cvoid}), eventloop(), this)
-        if err != 0
-            #TODO: this codepath is currently not tested
-            Libc.free(this.handle)
-            this.handle = C_NULL
-            throw(_UVError("uv_timer_init", err))
-        end
-
-        associate_julia_struct(this.handle, this)
-        finalizer(uvfinalize, this)
-
-        ccall(:uv_update_time, Cvoid, (Ptr{Cvoid},), eventloop())
-        ccall(:uv_timer_start,  Cint,  (Ptr{Cvoid}, Ptr{Cvoid}, UInt64, UInt64),
-              this, uv_jl_timercb::Ptr{Cvoid},
+        ccall(:jl_uv_update_timer_start, Cvoid,
+              (Ptr{Cvoid}, Any, Ptr{Cvoid}, Ptr{Cvoid}, UInt64, UInt64),
+              eventloop(), this, this.handle, uv_jl_timercb::Ptr{Cvoid},
               UInt64(round(timeout * 1000)) + 1, UInt64(round(interval * 1000)))
+        finalizer(uvfinalize, this)
         return this
     end
 end

src/jl_uv.c

@@ -1085,6 +1085,23 @@ JL_DLLEXPORT int jl_queue_work(work_cb_t work_func, void *work_args, void *work_
     return 0;
 }
 
+JL_DLLEXPORT void jl_uv_update_timer_start(uv_loop_t* loop, jl_value_t* jltimer,
+                                          uv_timer_t* uvtimer, uv_timer_cb cb,
+                                          uint64_t timeout, uint64_t repeat)
+{
+    JL_UV_LOCK();
+    int err = uv_timer_init(loop, uvtimer);
+    if (err)
+        abort();
+
+    jl_uv_associate_julia_struct((uv_handle_t*)uvtimer, jltimer);
+    uv_update_time(loop);
+    err = uv_timer_start(uvtimer, cb, timeout, repeat);
+    if (err)
+        abort();
+    JL_UV_UNLOCK();
+}
+
 JL_DLLEXPORT void jl_uv_stop(uv_loop_t* loop)
 {
     JL_UV_LOCK();