Hi, recently some users of my app upgrade MacOS to 15, and encounter hang when trying to get screen capture permission. After looking into this issue, I find out a repoducible way. If two processes of a same program both call CGDisplayStreamCreate/CGDisplayImageCreate API, the later one will hang(No need to be at almost same time).
Here are my demo codes.
#import <AVFoundation/AVFoundation.h>
#import <CoreGraphics/CoreGraphics.h>
#import <Foundation/Foundation.h>
int main(int argc, const char *argv[]) {
@autoreleasepool {
CGDirectDisplayID displayID = CGMainDisplayID();
CGDisplayStreamRef stream = CGDisplayStreamCreate(
displayID, 1, 1, kCVPixelFormatType_32BGRA, nil,
^(CGDisplayStreamFrameStatus status, uint64_t displayTime,
IOSurfaceRef frameSurface, CGDisplayStreamUpdateRef updateRef){
});
if (!stream) {
NSLog(@"Failed to create display stream!");
return 1;
} else {
NSLog(@"Create display stream success!");
CFRelease(stream);
}
}
sleep(10);
return 0;
}
The call of sleep is just to ensure I can run a second process of this program before the first one ends. It turns out that the first process checks the permission correctly and sleeps successfully. However the second process won't be able to print anything because it hangs when calling CGDisplayStreamCreate. Here is the output of sample:
Call graph:
2546 Thread_1315735 DispatchQueue_1: com.apple.main-thread (serial)
+ 2546 start (in dyld) + 2840 [0x196f8f274]
+ 2546 main (in testapp) + 76 [0x100ef7e38]
+ 2546 SLDisplayStreamCreate (in SkyLight) + 316 [0x19d38163c]
+ 2546 SLSDisplayStreamCreateProxying (in ScreenCaptureKit) + 816 [0x231e2d614]
+ 2546 _dispatch_semaphore_wait_slow (in libdispatch.dylib) + 76 [0x19715e278]
+ 2546 _dispatch_sema4_timedwait (in libdispatch.dylib) + 64 [0x19715dc78]
+ 2546 semaphore_timedwait_trap (in libsystem_kernel.dylib) + 8 [0x1972ceda8]
2546 Thread_1315737
2546 start_wqthread (in libsystem_pthread.dylib) + 8 [0x19730b0f0]
2546 _pthread_wqthread (in libsystem_pthread.dylib) + 364 [0x19730c424]
2546 __workq_kernreturn (in libsystem_kernel.dylib) + 8 [0x1972d0a64]
If I copy the program and run two different programs, the second program won't hang. This issue doesn't happen on MacOS early version. Can anybody help?
mikucy
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Translated Report (Full Report Below)
Version: 1.0.0 (2.0)
Code Type: X86-64 (Translated)
Parent Process: launchd [1]
User ID: 948009654
Date/Time: 2023-11-02 19:47:33.1522 +0800
OS Version: macOS 12.1 (21C52)
Report Version: 12
Anonymous UUID: 815896E6-939E-002C-08C6-C903A4B87DF4
Sleep/Wake UUID: F06CECA0-3643-4423-A6F4-1163217FF863
Time Awake Since Boot: 100000 seconds
Time Since Wake: 92675 seconds
System Integrity Protection: enabled
Crashed Thread: 0 CrBrowserMain Dispatch queue: com.apple.main-thread
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Application Specific Information:
Assertion failed: (mach_vm_map(mach_task_self(), &address, size, 0, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_COREGRAPHICS_BACKINGSTORES), port, 0, false, prot, prot, VM_INHERIT_SHARE) == KERN_SUCCESS), function backing_map, file CGSBackingStore.c, line 192.
Kernel Triage:
VM - Compressor failed a blocking pager_get
VM - Compressor failed a blocking pager_get
VM - Compressor failed a blocking pager_get
VM - Compressor failed a blocking pager_get
VM - Compressor failed a blocking pager_get
Thread 0 Crashed:: CrBrowserMain Dispatch queue: com.apple.main-thread
0 <translation info unavailable> 0x108107a20 ???
1 libsystem_kernel.dylib 0x7ff8023cd5e2 __sigreturn + 10
2 ??? 0x7fc103a4f190 ???
3 libsystem_c.dylib 0x7ff80234dd10 abort + 123
4 libsystem_c.dylib 0x7ff80234d0be __assert_rtn + 314
5 SkyLight 0x7ff8075129de backing_map + 550
6 SkyLight 0x7ff8072c82ad lock_window_backing + 557
7 SkyLight 0x7ff807369f41 SLSDeviceLock + 54
8 CoreGraphics 0x7ff8076e6550 ripd_Lock + 56
9 CoreGraphics 0x7ff807678772 RIPLayerBltShape + 490
10 CoreGraphics 0x7ff8076769c7 ripc_Render + 328
11 CoreGraphics 0x7ff8076737d4 ripc_DrawRects + 482
12 CoreGraphics 0x7ff807673565 CGContextFillRects + 145
13 CoreGraphics 0x7ff8076734c4 CGContextFillRect + 117
14 CoreGraphics 0x7ff807672fe8 CGContextClearRect + 52
15 HIToolbox 0x7ff80b6176e0 HIMenuBarView::DrawOnce(CGRect, CGRect, bool, HIMenuBarTextAppearance, CGContext*) + 110
16 HIToolbox 0x7ff80b617640 HIMenuBarView::DrawIntoWindow(unsigned int*, CGRect, double, CGRect, bool, HIMenuBarTextAppearance, CGContext*) + 410
17 HIToolbox 0x7ff80b53c146 HIMenuBarView::DrawSelf(short, __HIShape const*, CGContext*) + 280
18 HIToolbox 0x7ff80b53bd56 HIMenuBarView::DrawingDelegateHandler(OpaqueEventHandlerCallRef*, OpaqueEventRef*, void*) + 262
19 HIToolbox 0x7ff80b520d1d DispatchEventToHandlers(EventTargetRec*, OpaqueEventRef*, HandlerCallRec*) + 1391
20 HIToolbox 0x7ff80b52014e SendEventToEventTargetInternal(OpaqueEventRef*, OpaqueEventTargetRef*, HandlerCallRec*) + 333
21 HIToolbox 0x7ff80b51ffef SendEventToEventTargetWithOptions + 45
22 HIToolbox 0x7ff80b53b8d3 HIView::SendDraw(short, OpaqueGrafPtr*, __HIShape const*, CGContext*) + 325
23 HIToolbox 0x7ff80b53b399 HIView::RecursiveDrawComposited(__HIShape const*, __HIShape const*, unsigned int, HIView*, CGContext*, unsigned char, double) + 571
24 HIToolbox 0x7ff80b53b56d HIView::RecursiveDrawComposited(__HIShape const*, __HIShape const*, unsigned int, HIView*, CGContext*, unsigned char, double) + 1039
25 HIToolbox 0x7ff80b53add8 HIView::DrawComposited(short, OpaqueGrafPtr*, __HIShape const*, unsigned int, HIView*, CGContext*) + 832
26 HIToolbox 0x7ff80b53aa89 HIView::Render(unsigned int, CGContext*) + 51
27 HIToolbox 0x7ff80b5521a9 FlushWindowObject(WindowData*, void**, unsigned char) + 772
28 HIToolbox 0x7ff80b551c2f FlushAllBuffers(__CFRunLoopObserver*, unsigned long, void*) + 317
29 CoreFoundation 0x7ff8024c6f98 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
30 CoreFoundation 0x7ff8024c6e34 __CFRunLoopDoObservers + 543
31 CoreFoundation 0x7ff8024c5830 CFRunLoopRunSpecific + 446
32 HIToolbox 0x7ff80b5474f1 RunCurrentEventLoopInMode + 292
33 HIToolbox 0x7ff80b547118 ReceiveNextEventCommon + 284
34 HIToolbox 0x7ff80b546fe5 _BlockUntilNextEventMatchingListInModeWithFilter + 70
35 AppKit 0x7ff804e1bb4c _DPSNextEvent + 886
36 AppKit 0x7ff804e1a1b8 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 1411
37 AppKit 0x7ff804e0c5a9 -[NSApplication run] + 586
38 libqcocoa.dylib 0x11402762f QCocoaEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 2495
39 QtCore 0x11ace2acf QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 431
40 QtCore 0x11ace7042 QCoreApplication::exec() + 130
Anyone knows why it happens and how to fix it?