I see this on B2G. After coming back from offline, Gecko creates two TCP connections for first XHR request. After digging the source code, I found XHR.Open() would create a speculative connection, but the connection was closed immediately for |nsSocketTransportService::mGoingOffline == true|. So, later, XHR.Send() will cause another connection being created. But, |nsSocketTransportService::mGoingOffline| should be |false| since the device is online again. |nsSocketTransportService::SetOffline(true)| would make |mGoingOffline == true|, but |nsSocketTransportService::SetOffline(true)| does not reset |mGoingOffline|, so |mGoingOffline == true| is possible kept for first speculative connection.

Comment on attachment 666459 [details] [diff] [review] Reset mGoingOffline to fix speculative connect Review of attachment 666459 [details] [diff] [review]: ----------------------------------------------------------------- Patrick, this little patch seems logical to me but I'm guessing you or Honza know this code better than I do.

Comment on attachment 666459 [details] [diff] [review] Reset mGoingOffline to fix speculative connect Review of attachment 666459 [details] [diff] [review]: ----------------------------------------------------------------- adam?

Comment on attachment 666459 [details] [diff] [review] Reset mGoingOffline to fix speculative connect Nice fix! The socket thread will reset |mGoingOffline| after it clears its event queue. If we go back online before that happens, |mGoingOffline| should definitely reset.