Doesn't seem that this is a known issue. I will try and write a short reproducer and file an issue.
On Fri, Aug 5, 2022, 11:18 PM atd...@gmail.com <atd...@gmail.com> wrote: > Hi, > > I have a little concurrency problem. Seems that my Go-wasm-defined event > handlers run concurrently instead of synchronously. > > Basically, the event handler is called by runtime.handleEvent which calls > into the syscall/js defined version of it > > Link to source > <https://cs.opensource.google/go/go/+/master:src/runtime/lock_js.go;l=244?q=handlEeVE&sq=&ss=go%2Fgo:src%2Fruntime%2F> > // handleEvent gets invoked on a call from JavaScript into Go. It calls > the event handler of the syscall/js package > // and then parks the handler goroutine to allow other goroutines to run > before giving execution back to JavaScript. > // When no other goroutine is awake any more, beforeIdle resumes the > handler goroutine. Now that the same goroutine > // is running as was running when the call came in from JavaScript, > execution can be safely passed back to JavaScript. > func handleEvent() { > e := &event{ > gp: getg(), > returned: false, > } > events = append(events, e) > *eventHandler() // !!!!* > clearIdleID() > // wait until all goroutines are idle > e.returned = true > gopark(nil, nil, waitReasonZero, traceEvNone, 1) > events[len(events)-1] = nil > events = events[:len(events)-1] > // return execution to JavaScript > pause(getcallersp() - 16) > } > > In syscall/js, Link to source > <https://cs.opensource.google/go/go/+/master:src/syscall/js/func.go;l=69?q=handleEve&sq=&ss=go%2Fgo> > func handleEvent() { > cb := jsGo.Get("_pendingEvent") > if cb.IsNull() { > return > } > jsGo.Set("_pendingEvent", Null()) > id := uint32(cb.Get("id").Int()) > if id == 0 { // zero indicates deadlock > select {} > } > funcsMu.Lock() > f, ok := funcs[id] > funcsMu.Unlock() > if !ok { > Global().Get("console").Call("error", "call to released function") > return > } > this := cb.Get("this") > argsObj := cb.Get("args") > args := make([]Value, argsObj.Length()) > for i := range args { > args[i] = argsObj.Index(i) > } > *result := f(this, args) // My callback runs here* > cb.Set("result", result) > } > > > Basically, f causes a deadlock because it locks a mutex but never unlocks > before being called again in response to another JS event. > If I remove the lock, it's fine but he program should be incorrect as > event handlers should be run synchronously. > > *Tried to instrument the code to display the call stack. You can see > toward the end that there is an attempt to take a lock while handling the > focus event that has not been unlocked beforehand while processing the > click event.* > > 2022/08/05 22:24:25 focusTodo-App > wasm_exec.js:22 2022/08/05 22:24:25 LOCKING > ==================================================================== > wasm_exec.js:22 2022/08/05 22:24:25 LOCkED > ---------------------------------------------------------------------- > wasm_exec.js:22 2022/08/05 22:24:25 6 > wasm_exec.js:22 runtime.Callers > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.SDEBUG > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1 > wasm_exec.js:22 syscall/js.handleEvent > wasm_exec.js:22 runtime.handleEvent > wasm_exec.js:22 runtime.goexit > wasm_exec.js:22 2022/08/05 22:24:25 UNLOCKING > ==================================================================== > wasm_exec.js:22 2022/08/05 22:24:25 7 > wasm_exec.js:22 runtime.Callers > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.SDEBUG > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.freelock > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1 > wasm_exec.js:22 syscall/js.handleEvent > wasm_exec.js:22 runtime.handleEvent > wasm_exec.js:22 runtime.goexit > wasm_exec.js:22 2022/08/05 22:24:25 UNLOCkED > ---------------------------------------------------------------------- > wasm_exec.js:22 2022/08/05 22:24:32 focusTodo-App > wasm_exec.js:22 2022/08/05 22:24:32 LOCKING > ==================================================================== > wasm_exec.js:22 2022/08/05 22:24:32 LOCkED > ---------------------------------------------------------------------- > wasm_exec.js:22 2022/08/05 22:24:32 6 > wasm_exec.js:22 runtime.Callers > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.SDEBUG > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1 > wasm_exec.js:22 syscall/js.handleEvent > wasm_exec.js:22 runtime.handleEvent > wasm_exec.js:22 runtime.goexit > wasm_exec.js:22 2022/08/05 22:24:32 UNLOCKING > ==================================================================== > wasm_exec.js:22 2022/08/05 22:24:32 7 > wasm_exec.js:22 runtime.Callers > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.SDEBUG > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.freelock > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1 > wasm_exec.js:22 syscall/js.handleEvent > wasm_exec.js:22 runtime.handleEvent > wasm_exec.js:22 runtime.goexit > wasm_exec.js:22 2022/08/05 22:24:32 UNLOCkED > ---------------------------------------------------------------------- > > > *wasm_exec.js:22 2022/08/05 22:24:32 > clickactive-filter-anchorwasm_exec.js:22 2022/08/05 22:24:32 LOCKING > ====================================================================wasm_exec.js:22 > 2022/08/05 22:24:32 LOCkED > -----------------------------------------------------------------*----- > wasm_exec.js:22 2022/08/05 22:24:32 6 > wasm_exec.js:22 runtime.Callers > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.SDEBUG > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1 > wasm_exec.js:22 syscall/js.handleEvent > wasm_exec.js:22 runtime.handleEvent > wasm_exec.js:22 runtime.goexit > > *wasm_exec.js:22 2022/08/05 22:24:32 focusTodo-Appwasm_exec.js:22 > 2022/08/05 22:24:32 LOCKING* > ==================================================================== > wasm_exec.js:22 fatal error: all goroutines are asleep - deadlock! > wasm_exec.js:22 > wasm_exec.js:22 goroutine 1 [chan receive]: > wasm_exec.js:22 > github.com/atdiar/particleui.(*Router).ListenAndServe(0x103d940, > {0x4d820, 0x8}, 0x4c6300, 0x61028) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/router.go:467 > +0x3a > wasm_exec.js:22 main.main() > wasm_exec.js:22 /home/atd/Desktop/Projects/todomvc/main.go:228 +0x1db > wasm_exec.js:22 > wasm_exec.js:22 goroutine 7 [semacquire]: > wasm_exec.js:22 sync.runtime_SemacquireMutex(0x2602c4, 0x0, 0x1) > wasm_exec.js:22 /usr/local/go/src/runtime/sema.go:71 +0x2 > wasm_exec.js:22 sync.(*Mutex).lockSlow(0x2602c0) > wasm_exec.js:22 /usr/local/go/src/sync/mutex.go:162 +0x26 > wasm_exec.js:22 sync.(*Mutex).Lock(0x2602c0) > wasm_exec.js:22 /usr/local/go/src/sync/mutex.go:81 +0x7 > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1({{} > <http://github.com/atdiar/particleui/drivers/js.glob..func2.1(%7B%7B%7D>, > 0x7ff8000100000018, 0x11d3848}, {0x121b1e0, 0x1, 0x1}) > wasm_exec.js:22 > /home/atd/Desktop/Projects/particleui/drivers/js/events.go:106 +0x21 > wasm_exec.js:22 syscall/js.handleEvent() > wasm_exec.js:22 /usr/local/go/src/syscall/js/func.go:94 +0x26 > wasm_exec.js:22 syscall/js.Value.Call({{}, 0x7ff800010000003e, 0x410740}, > {0x4ab3f, 0x5}, {0x0, 0x0, 0x0}) > wasm_exec.js:22 /usr/local/go/src/syscall/js/js.go:379 +0x3 > wasm_exec.js:22 > github.com/atdiar/particleui/drivers/js.glob..func10.7.2({0x8e540 > <http://github.com/atdiar/particleui/drivers/js.glob..func10.7.2(%7B0x8e540>, > 0x1206aa0}) > wasm_exec.js:22 > /home/atd/Desktop/Projects/particleui/drivers/js/javascript.go:873 +0x57 > wasm_exec.js:22 github.com/atdiar/particleui.(*MutationHandler).Handle(.. > .) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/mutation.go:113 > wasm_exec.js:22 github.com/atdiar/particleui.(*mutationHandlers).Handle(.. > .) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/mutation.go:95 > wasm_exec.js:22 > github.com/atdiar/particleui.(*MutationCallbacks).DispatchEvent(0x40c148, > {0x8e540, 0x1206aa0}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/mutation.go:62 > +0x3c > wasm_exec.js:22 github.com/atdiar/particleui.(*Element).Set(0x4c6240, > {0x4ab21, 0x5}, {0x4ff87, 0xd}, {0x8e258, 0x121b1c0}, {0x0, 0x0, 0x0}) > wasm_exec.js:22 > /home/atd/Desktop/Projects/particleui/uielement.go:1317 +0x7f > wasm_exec.js:22 github.com/atdiar/particleui.(*Router).GoTo(0x103d940, > {0x745dd0, 0x7}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/router.go:177 > +0x4b > wasm_exec.js:22 > github.com/atdiar/particleui.(*Router).NewLink.func4({0x8e540 > <http://github.com/atdiar/particleui.(*Router).NewLink.func4(%7B0x8e540>, > 0x1206960}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/router.go:859 > +0xf > wasm_exec.js:22 github.com/atdiar/particleui.(*MutationHandler).Handle(.. > .) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/mutation.go:113 > wasm_exec.js:22 github.com/atdiar/particleui.(*mutationHandlers).Handle(.. > .) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/mutation.go:95 > wasm_exec.js:22 > github.com/atdiar/particleui.(*MutationCallbacks).DispatchEvent(0x40c708, > {0x8e540, 0x1206960}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/mutation.go:62 > +0x3c > wasm_exec.js:22 github.com/atdiar/particleui.(*Element).Set(0x7852c0, > {0x4ab21, 0x5}, {0x4d3e8, 0x8}, {0x8e198, 0x213128}, {0x0, 0x0, 0x0}) > wasm_exec.js:22 > /home/atd/Desktop/Projects/particleui/uielement.go:1317 +0x7f > wasm_exec.js:22 github.com/atdiar/particleui.Link.Activate({0x7852c0} > <http://github.com/atdiar/particleui.Link.Activate(%7B0x7852c0%7D>, > {0x1210be0, 0x1, 0x1}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/router.go:742 > +0x7 > wasm_exec.js:22 > github.com/atdiar/particleui/drivers/js.Anchor.FromLink.func3({0x8e6d0 > <http://github.com/atdiar/particleui/drivers/js.Anchor.FromLink.func3(%7B0x8e6d0>, > 0x1206910}) > wasm_exec.js:22 > /home/atd/Desktop/Projects/particleui/drivers/js/javascript.go:1842 +0xf > wasm_exec.js:22 github.com/atdiar/particleui.EventHandler.Handle(...) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/event.go:198 > wasm_exec.js:22 > github.com/atdiar/particleui.EventListeners.Handle({0x563b90} > <http://github.com/atdiar/particleui.EventListeners.Handle(%7B0x563b90%7D>, > {0x8e6d0, 0x1206910}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/event.go:129 > +0x69 > wasm_exec.js:22 github.com/atdiar/particleui.(*Element).Handle(0x785740, > {0x8e6d0, 0x1206910}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/uielement.go:449 > +0x7 > wasm_exec.js:22 > github.com/atdiar/particleui.(*Element).DispatchEvent(0x785740, {0x8e6d0, > 0x1206910}) > wasm_exec.js:22 /home/atd/Desktop/Projects/particleui/uielement.go:482 > +0x11 > wasm_exec.js:22 github.com/atdiar/particleui/drivers/js.glob..func2.1({{} > <http://github.com/atdiar/particleui/drivers/js.glob..func2.1(%7B%7B%7D>, > 0x7ff8000100000133, 0x11d2e10}, {0x11f1fb0, 0x1, 0x1}) > wasm_exec.js:22 > /home/atd/Desktop/Projects/particleui/drivers/js/events.go:177 +0xe3 > wasm_exec.js:22 syscall/js.handleEvent() > wasm_exec.js:22 /usr/local/go/src/syscall/js/func.go:94 +0x26 > > > Any idea? > > -- > You received this message because you are subscribed to a topic in the > Google Groups "golang-nuts" group. > To unsubscribe from this topic, visit > 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