I did some preliminary code inspection. The two playback endpoints share
the same `SrsLiveStream` instance. After the first one disconnects,
`alive_` is set to false.
```
  alive_ = true;
  err = do_serve_http(w, r);
  alive_ = false;
```

In the `SrsHttpStreamServer::http_unmount(SrsRequest* r)` function,
`stream->alive()` is already false, so `mux.unhandle` will free the
`SrsLiveStream`. This causes the other connection coroutine to return to
its execution environment after the `SrsLiveStream` instance has already
been freed.
```
    // Wait for cache and stream to stop.
    int i = 0;
    for (; i < 1024; i++) {
        if (!cache->alive() && !stream->alive()) {
            break;
        }
        srs_usleep(100 * SRS_UTIME_MILLISECONDS);
    }

    // Unmount the HTTP handler, which will free the entry. Note that we must free it after cache and
    // stream stopped for it uses it.
    mux.unhandle(entry->mount, stream.get());
```

`alive_` was changed from a `bool` to an `int` to ensure that
`mux.unhandle` is only executed after each connection's `serve_http` has
exited.

---------

Co-authored-by: liumengte <liumengte@visionular.com>
Co-authored-by: winlin <winlinvip@gmail.com>

I did some preliminary code inspection. The two playback endpoints share
the same `SrsLiveStream` instance. After the first one disconnects,
`alive_` is set to false.
```
  alive_ = true;
  err = do_serve_http(w, r);
  alive_ = false;
```

In the `SrsHttpStreamServer::http_unmount(SrsRequest* r)` function,
`stream->alive()` is already false, so `mux.unhandle` will free the
`SrsLiveStream`. This causes the other connection coroutine to return to
its execution environment after the `SrsLiveStream` instance has already
been freed.
```
    // Wait for cache and stream to stop.
    int i = 0;
    for (; i < 1024; i++) {
        if (!cache->alive() && !stream->alive()) {
            break;
        }
        srs_usleep(100 * SRS_UTIME_MILLISECONDS);
    }

    // Unmount the HTTP handler, which will free the entry. Note that we must free it after cache and
    // stream stopped for it uses it.
    mux.unhandle(entry->mount, stream.get());
```

`alive_` was changed from a `bool` to an `int` to ensure that
`mux.unhandle` is only executed after each connection's `serve_http` has
exited.

---------

Co-authored-by: liumengte <liumengte@visionular.com>
Co-authored-by: winlin <winlinvip@gmail.com>

…0.11 (#4164)

When stopping the stream, it will wait for the HTTP Streaming to exit.
If the HTTP Streaming goroutine hangs, it will not exit automatically.

```cpp
void SrsHttpStreamServer::http_unmount(SrsRequest* r)
{
    SrsUniquePtr<SrsLiveStream> stream(entry->stream);
    if (stream->entry) stream->entry->enabled = false;
    srs_usleep(...); // Wait for about 120s.
    mux.unhandle(entry->mount, stream.get()); // Free stream.
}

srs_error_t SrsLiveStream::serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r)
{
    err = do_serve_http(w, r); // If stuck in here for 120s+
    alive_viewers_--; // Crash at here, because stream has been deleted.
```

We should notify http stream connection to interrupt(expire):

```cpp
void SrsHttpStreamServer::http_unmount(SrsRequest* r)
{
    SrsUniquePtr<SrsLiveStream> stream(entry->stream);
    if (stream->entry) stream->entry->enabled = false;
    stream->expire(); // Notify http stream to interrupt.
```

Note that we should notify all viewers pulling stream from this http
stream.

Note that we have tried to fix this issue, but only try to wait for all
viewers to quit, without interrupting the viewers, see
#4144


---------

Co-authored-by: Jacob Su <suzp1984@gmail.com>

)

When stopping the stream, it will wait for the HTTP Streaming to exit.
If the HTTP Streaming goroutine hangs, it will not exit automatically.

```cpp
void SrsHttpStreamServer::http_unmount(SrsRequest* r)
{
    SrsUniquePtr<SrsLiveStream> stream(entry->stream);
    if (stream->entry) stream->entry->enabled = false;
    srs_usleep(...); // Wait for about 120s.
    mux.unhandle(entry->mount, stream.get()); // Free stream.
}

srs_error_t SrsLiveStream::serve_http(ISrsHttpResponseWriter* w, ISrsHttpMessage* r)
{
    err = do_serve_http(w, r); // If stuck in here for 120s+
    alive_viewers_--; // Crash at here, because stream has been deleted.
```

We should notify http stream connection to interrupt(expire):

```cpp
void SrsHttpStreamServer::http_unmount(SrsRequest* r)
{
    SrsUniquePtr<SrsLiveStream> stream(entry->stream);
    if (stream->entry) stream->entry->enabled = false;
    stream->expire(); // Notify http stream to interrupt.
```

Note that we should notify all viewers pulling stream from this http
stream.

Note that we have tried to fix this issue, but only try to wait for all
viewers to quit, without interrupting the viewers, see
#4144

---------

Co-authored-by: Jacob Su <suzp1984@gmail.com>