From dff742ad27efa474ec04accdbf422c9acfd3e30e Mon Sep 17 00:00:00 2001 From: Hikaru Nishida Date: Tue, 15 Oct 2019 10:07:34 +0900 Subject: [PATCH] ui: Fix hanging up Cocoa display on macOS 10.15 (Catalina) macOS API documentation says that before applicationDidFinishLaunching is called, any events will not be processed. However, some events are fired before it is called in macOS Catalina. This causes deadlock of iothread_lock in handleEvent while it will be released after the app_started_sem is posted. This patch avoids processing events before the app_started_sem is posted to prevent this deadlock. Buglink: https://bugs.launchpad.net/qemu/+bug/1847906 Signed-off-by: Hikaru Nishida Message-id: 20191015010734.85229-1-hikarupsp@gmail.com Signed-off-by: Gerd Hoffmann --- ui/cocoa.m | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/ui/cocoa.m b/ui/cocoa.m index f12e21df6e..fbb5b1b45f 100644 --- a/ui/cocoa.m +++ b/ui/cocoa.m @@ -134,6 +134,7 @@ NSArray * supportedImageFileTypes; static QemuSemaphore display_init_sem; static QemuSemaphore app_started_sem; +static bool allow_events; // Utility functions to run specified code block with iothread lock held typedef void (^CodeBlock)(void); @@ -729,6 +730,16 @@ QemuCocoaView *cocoaView; - (bool) handleEvent:(NSEvent *)event { + if(!allow_events) { + /* + * Just let OSX have all events that arrive before + * applicationDidFinishLaunching. + * This avoids a deadlock on the iothread lock, which cocoa_display_init() + * will not drop until after the app_started_sem is posted. (In theory + * there should not be any such events, but OSX Catalina now emits some.) + */ + return false; + } return bool_with_iothread_lock(^{ return [self handleEventLocked:event]; }); @@ -1156,6 +1167,7 @@ QemuCocoaView *cocoaView; - (void)applicationDidFinishLaunching: (NSNotification *) note { COCOA_DEBUG("QemuCocoaAppController: applicationDidFinishLaunching\n"); + allow_events = true; /* Tell cocoa_display_init to proceed */ qemu_sem_post(&app_started_sem); }