We're observing new crashes specifically on iOS 18.4 devices with this pattern:
Exception Type: SIGTRAP
Exception Codes: fault addr: 0x000000019bc0f088
Crashed Thread: 0
Thread 0
0 libsystem_malloc.dylib _xzm_xzone_malloc_from_tiny_chunk.cold.1 + 36
1 libsystem_malloc.dylib __xzm_xzone_malloc_from_tiny_chunk + 612
2 libsystem_malloc.dylib __xzm_xzone_find_and_malloc_from_tiny_chunk + 112
3 libsystem_malloc.dylib __xzm_xzone_malloc_tiny_outlined + 312
4 CoreGraphics CG::Path::Path(CG::Path const&) + 132
5 CoreGraphics _CGPathCreateMutableCopyByTransformingPath + 112
6 CoreGraphics _CGFontCreateGlyphPath + 144
7 CoreGraphics _CGGlyphBuilderLockBitmaps + 1112
8 CoreGraphics _render_glyphs + 292
9 CoreGraphics _draw_glyph_bitmaps + 1116
10 CoreGraphics _ripc_DrawGlyphs + 1464
11 CoreGraphics CG::DisplayList::executeEntries(std::__1::__wrap_iter<std::__1::shared_ptr<CG::DisplayListEntry const>*>, std::__1::__wrap_iter<std::__1::shared_ptr<CG::DisplayListEntry const>*>, CGContextDelegate*, CGRenderingState*, CGGStack*, CGRect const*, __CFDictionary const*, bool) + 1328
12 CoreGraphics _CGDisplayListDrawInContextDelegate + 340
13 QuartzCore _CABackingStoreUpdate_ + 612
14 QuartzCore ____ZN2CA5Layer8display_Ev_block_invoke + 120
15 QuartzCore -[CALayer _display] + 1512
16 QuartzCore CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 420
17 QuartzCore CA::Context::commit_transaction(CA::Transaction*, double, double*) + 476
18 QuartzCore CA::Transaction::commit() + 644
19 UIKitCore ___34-[UIApplication _firstCommitBlock]_block_invoke_2 + 36
20 CoreFoundation ___CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 28
21 CoreFoundation ___CFRunLoopDoBlocks + 352
22 CoreFoundation ___CFRunLoopRun + 868
23 CoreFoundation _CFRunLoopRunSpecific + 572
24 GraphicsServices _GSEventRunModal + 168
25 UIKitCore -[UIApplication _run] + 816
26 UIKitCore _UIApplicationMain + 336
27 app _main + 132
28 dyld __dyld_process_info_create + 33284
Key Observations:
Crash occurs during font glyph path creation (CGFontCreateGlyphPath)
Involves memory allocation in malloc's xzone implementation
100% reproducible on iOS 18.4, not seen in prior OS versions
Occurs during standard CALayer rendering operations
Not tied to any specific font family or glyph content
Questions for Apple:
Is this crash signature recognized as a known issue in iOS 18.4's CoreGraphics?
Could changes to xzone memory management in iOS 18.4 interact poorly with font rendering?
Are there specific conditions that might trigger SIGTRAP in CGPathCreateMutableCopyByTransformingPath?
Any recommended mitigations for text rendering while awaiting system updates?
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Title: Frequent SIGSEGV crashes in QuartzCore's copy_image (iOS 18.4)
We're experiencing numerous crashes with the following signature:
Exception Codes: fault addr: 0x00000000000000e0
Crashed Thread: 0
Thread 0
0 QuartzCore CA::Render::copy_image(CGImage*, CGColorSpace*, unsigned int, double, double) + 1972
1 QuartzCore CA::Render::copy_image(CGImage*, CGColorSpace*, unsigned int, double, double) + 1260
2 QuartzCore CA::Render::prepare_image(CGImage*, CGColorSpace*, unsigned int, double) + 24
3 QuartzCore CA::Layer::prepare_contents(CALayer*, CA::Transaction*) + 220
4 QuartzCore CA::Layer::prepare_commit(CA::Transaction*) + 284
5 QuartzCore CA::Context::commit_transaction(CA::Transaction*, double, double*) + 488
6 QuartzCore CA::Transaction::commit() + 644
7 UIKitCore ___34-[UIApplication _firstCommitBlock]_block_invoke_2 + 36
8 CoreFoundation ___CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 28
9 CoreFoundation ___CFRunLoopDoBlocks + 352
10 CoreFoundation ___CFRunLoopRun + 868
11 CoreFoundation _CFRunLoopRunSpecific + 572
12 GraphicsServices _GSEventRunModal + 168
13 UIKitCore -[UIApplication _run] + 816
14 UIKitCore _UIApplicationMain + 336
15 kugou _main + 132
16 dyld __dyld_process_info_create + 33284
Observations:
1.Crashes consistently occur in Core Animation's image processing pipeline
2.100% of occurrences are on iOS 18.4 devices
3.Crash signature suggests memory access violation during image/copy operations
4.Not tied to any specific device model
Questions for Apple:
1.Is this crash pattern recognized as a known issue in iOS 18.4?
2.Are there specific conditions that could trigger SEGV_ACCERR in CA::Render::copy_image?
3.Could this be related to color space handling or image format requirements changes?
4.Any recommended workarounds while waiting for a system update?
Title:
SIGTRAP Crash in QuartzCore/CALayer during UI Lifecycle Changes
Description:
My app is experiencing occasional crashes triggered by a SIGTRAP signal during UI transitions (e.g., scene lifecycle changes, animations). The crash occurs in QuartzCore/UIKitCore code paths, and no business logic appears in the stack trace.
Crash Context:
Crash occurs sporadically during UI state changes (e.g., app backgrounding, view transitions).
Stack trace involves pthread_mutex_destroy, CA::Layer::commit_if_needed, and UIKit scene lifecycle methods.
Full crash log snippet:
Signal: SIGTRAP
Thread 0 Crashed:
0 libsystem_platform.dylib 0x... [symbol: _platform_memset$VARIANT$Haswell]
2 libsystem_pthread.dylib pthread_mutex_destroy + 64
3 QuartzCore CA::Layer::commit_if_needed(...)
4 UIKitCore UIScenePerformActionsWithLifecycleActionMask + 112
5 CoreFoundation _CFXNotificationPost + 736
Suspected Causes:
Threading Issue: Potential race condition in pthread_mutex destruction (e.g., mutex used after free).
UI Operation on Background Thread: CALayer/UIKit operations not confined to the main thread.
Lifecycle Mismatch: Scene/UI updates after deallocation (e.g., notifications triggering late UI changes).
Troubleshooting Attempted:
Enabled Zombie Objects – no obvious over-released objects detected.
Thread Sanitizer shows no clear data races.
Verified UIKit/CoreAnimation operations are dispatched to MainThread.
Request for Guidance:
Are there known issues with CA::Layer::commit_if_needed and scene lifecycle synchronization?
How to debug SIGTRAP in system frameworks when no app code is in the stack?
Recommended tools/approaches to isolate the mutex destruction issue.
Background
When I receive the InterruptionBegan notification (the interruption type is AVAudioSessionInterruptionTypeBegan) , I pause playing music.
When I receive the InterruptionEnded notification (the interruption type is AVAudioSessionInterruptionTypeEnded), I resume playing music.
however, sometimes i has got the error code: AVAudioSessionErrorCodeCannotInterruptOthers (560557684)
Some Solutions
I searched stackoverflow, there's some similar questions, and some solutions here are not very satisfying as :
I don't want my app to mix with others, and once again, it all works most of the time.
My app already uses remote control events so this doesn't solve anything.
Questions
1.Have someone ever encountered this problem ?
2.Can we solve this problem and how ?
3.In addition, I noticed that there's property named otherAudioPlaying in AVAudioSession, we can know there's another app is playing,the quetion is if we can know which app is playing ?