51352 2010-12-20 13:23:25 -0800 Web process should only spin a run loop while waiting for replies to synchronous messages that invoke UI 2015-06-18 14:56:35 -0700 1 1 1 Unclassified WebKit WebKit2 528+ (Nightly build) PC Windows XP RESOLVED INVALID InRadar, PlatformOnly P2 Normal --- 51351 53211 1 aroben webkit-unassigned andersca sam oldest_to_newest 324537 0 aroben 2010-12-20 13:23:25 -0800 As described in bug 51351, having the UI process respond to synchronous messages from the web process on the main thread can result in deadlocks when windowed plugins are involved. We're going to move all synchronous message processing off the main thread by default in the UI process. But synchronous messages that result in needing to display UI (e.g., WebPageProxy::RunJavaScriptAlert) require doing so on the main thread. In those cases, the web process will need to spin a run loop while waiting for the message reply to avoid the kinds of deadlocks described in bug 51351. 324541 1 aroben 2010-12-20 13:25:05 -0800 <rdar://problem/8790537> 340676 2 aroben 2011-01-26 18:10:29 -0800 As described in bug 51351 comment 4, we're going to spin a run loop while waiting for a reply to all synchronous messages. Once bug 51351 is fixed we'll only spin a run loop while waiting for replies to synchronous messages that present UI in the UI process. 383200 3 aroben 2011-04-11 09:08:56 -0700 (In reply to comment #2) > As described in bug 51351 comment 4, we're going to spin a run loop while waiting for a reply to all synchronous messages. Bug 58239 now covers this strategy. > Once bug 51351 is fixed we'll only spin a run loop while waiting for replies to synchronous messages that present UI in the UI process. We'll continue to use this bug to track this future improvement. 1103045 4 andersca 2015-06-18 14:56:35 -0700 We got rid of WK2 for Windows so this no longer applies.