Filed an issue with a reproducer ; https://github.com/golang/go/issues/54328
On Sunday, August 7, 2022 at 12:08:33 AM UTC+2 atd...@gmail.com wrote: > 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 >> https://groups.google.com/d/topic/golang-nuts/a2PQjh4D6rw/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> golang-nuts...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/274b9c4c-f79b-4d62-8f36-e84a377eb482n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/golang-nuts/274b9c4c-f79b-4d62-8f36-e84a377eb482n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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