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iOS 26 EXC_BREAKPOINT in libmalloc _xzm_xzone_malloc_freelist_outlined during NSData base64 encoding
We are seeing a low-volume but persistent crash on iOS 26 that surfaces inside Foundation's base64 encoder, and we would like to see if and how we could prevent that crash 2026-08-14_10-47-14.9181_-0500-5b74aa117551b30ab7696e1d90c129b97ab1e42f.crash - (nonnull NSString *)pnd_UTF8Base64 { NSData *encodedData = [self dataUsingEncoding:NSUTF8StringEncoding]; if (encodedData == nil || encodedData.length == 0) { return @""; } NSData *safeData = [NSData dataWithBytes:encodedData.bytes length:encodedData.length]; return [safeData base64EncodedStringWithOptions:0]; } Questions: Is our reading correct that _xzm_xzone_malloc_freelist_outlined indicates the freelist was ALREADY corrupted before this allocation (double-free / use-after-free / buffer overflow somewhere else), and that this base64 malloc is merely the first allocation to detect it (a 'canary'), not the cause? Did the iOS 26 xzone allocator add/strengthen freelist integrity checks such that latent corruption that previously went unnoticed now traps here? What is the recommended way to pin down the real corruptor in a shipping app where this reproduces only occasionally on end-user devices (MallocStackLogging, Guard Malloc / libgmalloc, MallocScribble, Address Sanitizer, MallocNanoZone settings)? Are any of these usable/meaningful against the xzone allocator? Is there any process-level or per-allocation API to validate heap integrity that is safe on the xzone allocator (e.g. malloc_zone_check behavior on iOS 26)? Any guidance on interpreting this signature and isolating the root cause would be appreciated. Thanks.
1
0
409
Aug ’26
Application Hangs with Nested LazyVStack When Accessibility Inspector is Active
Description I've encountered a consistent hang/freeze issue in SwiftUI applications when using nested LazyVStack containers with Accessibility Inspector (simulator) or VoiceOver (physical device) enabled. The application becomes completely unresponsive and must be force-quit. Importantly, this hang occurs in a minimal SwiftUI project with no third-party dependencies, suggesting this is a framework-level issue with the interaction between SwiftUI's lazy view lifecycle and the accessibility system. Reproduction Steps I've created a minimal reproduction project available here: https://github.com/pendo-io/SwiftUI_Hang_Reproduction To Reproduce: Create a SwiftUI view with the following nested LazyVStack structure: struct NestedLazyVStackView: View { @State private var outerSections: [Int] = [] @State private var innerRows: [Int: [Int]] = [:] var body: some View { ScrollView { LazyVStack(alignment: .leading, spacing: 24) { ForEach(outerSections, id: \.self) { section in VStack(alignment: .leading, spacing: 8) { Text("Section #\(section)") // Nested LazyVStack LazyVStack(alignment: .leading, spacing: 2) { ForEach(innerRows[section] ?? [], id: \.self) { row in Text("Section #\(section) - Row #\(row)") .onAppear { // Load more data when row appears loadMoreInner(section: section) } } } } .onAppear { // Load more sections when section appears loadMoreOuter() } } } } } } Enable Accessibility Inspector in iOS Simulator: Xcode → Open Developer Tool → Accessibility Inspector Select your running simulator Enable Inspection mode (eye icon) Navigate to the view and start scrolling Result: The application hangs and becomes unresponsive within a few seconds of scrolling Expected Behavior The application should remain responsive when Accessibility Inspector or VoiceOver is enabled, allowing users to scroll through nested lazy containers without freezing. Actual Behavior The application freezes/hangs completely CPU usage may spike The app must be force-quit to recover The hang occurs consistently and is reproducible Workaround 1: Replace inner LazyVStack with VStack LazyVStack { ForEach(...) { section in VStack { // ← Changed from LazyVStack ForEach(...) { row in ... } } } } Workaround 2: Embed in TabView TabView { NavigationStack { NestedLazyVStackView() // ← Same nested structure, but no hang } .tabItem { ... } } Interestingly, wrapping the entire navigation stack in a TabView prevents the hang entirely, even with the nested LazyVStack structure intact. Questions for Apple Is there a known issue with nested LazyVStack containers and accessibility traversal? Why does wrapping the view in a TabView prevent the hang? Are there recommended patterns for using nested lazy containers with accessibility support? Is this a timing issue, a deadlock, or an infinite loop in the accessibility system? Why that happens? Reproduction Project A complete, minimal reproduction project is available at: https://github.com/pendo-io/SwiftUI_Hang_Reproduction
8
0
1.3k
Jun ’26
accessibilityRespondsToUserInteraction return true on Simulator but false on device
I am seeing a strange issue where NSObject accessibilityRespondsToUserInteraction returns true on Simulator but false on device. Checking the same object on simulator with Accessibility inspector I see the object traits as image so why would it return true in that case? Are there any other way to check the the item might be accessibilityRespondsToUserInteraction OR Clickable beside that property and traits? (Or is it just another bug)
1
0
179
Jun ’25
Integrating binary inside Framework via SPM
So I will summary an issue one of our clients has asked us on GitHub: https://github.com/pendo-io/pendo-mobile-sdk/issues/233 Project that is a custom framework that uses different SPM packages (one of them is Binary package), we have our main logic inside that framework and we have different targets that use this framework, everything works on the simulator, but running the app on the actual device provokes a crash saying "Binary framework was not found". We have like 20 other SPM packages that work fine, this is the first one we have an issue with. Please note I understand that SPM will not copy paste the Binary for the magic framework as it does for the apps so I suggested to embed it manually. So my question is what the best(easy) way to do it. Please refer to the following issue for more details: https://github.com/pendo-io/pendo-mobile-sdk/issues/233
0
0
228
Mar ’25
Running dynamically loaded js code in iOS
Hello, We're developing an SDK for iOS and need clarification on Apple's policies regarding the use of JavaScriptCore. Specifically, we want to understand if it's permissible to execute JavaScript code provided by our customers using JavaScriptCore. Our use case is as follows: Our customers will supply JavaScript code snippets, which our SDK will receive as text. The intention is to run these code snippets via JavaScriptCore to present interactive guides or dynamic content to the end-users of the app. Would executing customer-provided JavaScript code in this manner be considered a violation of Apple's App Store guidelines?
5
0
889
Feb ’25
Crash objc_retain_x0
Attaching several crash traces: 2024-02-29_22-48-33.6864_-0600-3f948243e21b4c68d77a38d9cf1cecfdfe2c1565.crash 2024-03-04_15-00-02.9335_-0600-75000cd5acd63ba1434f2ffb3648b97259dddb88.crash 2024-03-05_08-55-47.2097_-0500-f682b25663107ad46f091d65f402f2be31f3f3c6.crash 2024-03-11_08-09-00.4057_-0400-e37d1a635d51afbb67ac38b42dd79c1718a408e8.crash 2024-03-15_16-20-22.6446_-0600-d4ebccf455e8305038ca564a39a5661a1dce6231.crash The final code: - (NSObject*)objectAtIndex:(NSUInteger)index { if (index < self.count) { return [self.embeddedArray objectAtIndex:index]; } else { [PNDErrorReporting reportError:PNDErrorReasonTypeSafeCollectionCrashPrevented message:@"Error msg"]; return nil; } } We subclass NSMutableArray to prevent potential crashes. but we encounter a new crash in our sdk for one of the clients. Also we noticed the stack trace skipped one of the frames (stack calls) in the crash report, in which cases the stack trace wont be identical to the actual code (beside inline)?
8
0
2.5k
Jun ’24
NSarray crashes with different exceptions from the same place
It seems that that all the crashes are coming from the same place BUT the error is slightly different. Attaching the code that responsible for the crash: static NSString * const kDelimiter = @"#$@"; + (PNDArray *)getObjectsFromData:(NSData *)data { NSString *dataStr = [[NSString alloc] initWithData:data encoding:encoding]; dataStr = [dataStr stringByReplacingOccurrencesOfString:@"\\u0000" withString:@""]; NSArray *components = [dataStr componentsSeparatedByString:kDelimiter]; NSMutableArray *result = [NSMutableArray array]; for (NSString *jsonStr in components) { if (jsonStr != nil && jsonStr.length != 0 && ![jsonStr hasPrefix:kBatchUUID]) { [result addObject:jsonStr]; } } return [PNDArray arrayWithArray:result]; } 2024-04-16_17-15-34.1922_-0600-dfa2faecf702f23e3f6558bea986de4f62851761.crash 2024-04-24_04-56-53.4664_-0500-6b125d3d03b7e497b6be339c2abb52f29658824b.crash 2024-04-25_11-13-53.1326_-0700-bfe370be3eae8d65f465eac714905dd3d13aa665.crash 2024-05-03_11-47-36.6085_-0500-2793587e7ed1c02b0e4334bbc3aa0bd7f7a0cf3d.crash 2024-05-05_10-49-40.5969_-0700-4d86636b0877fceb8c0cdb9586ee16dfb0a9c934.crash
15
0
2.4k
Jun ’24
Check if NSMicrophoneUsageDescription exists
In our third party SDK we would like to use microphone (as optional feature) in case the hosting app allows it. From the docs requestRecordPermission will crash if no NSMicrophoneUsageDescription exists in the hosting app info.plist. Obviously I don't want to crash the app. I would like to check if the hosting app will allow me to call requestRecordPermission before calling it? Is it possible
1
0
1.1k
Jun ’24
Install .app file on simulator m1
I have a general question that confusing me. I am on M1 and I can build my app on Xcode (or create an archive) for device. Looking in to derived data I can see Debug-iphones (and simulators) folders, I can get the .app and drag/drop it to the simulator. When trying to run the app the app will crash with error: EXEC 14 Binary with wrong platform I understand that it wasn't build for simulators but rather it was build for devices and there fore the crash, but when thinking about it I dont understand why? (at least theoretically it shouldn't crash as it was build for arm64 ). Inspected the binary with lipo it was build for arm64. Comparing the binaries for simulator and device (with otool) I dont see a lot of difference except the rpath. So how does IOS knows it was build for device and not simulator (wrong platform)? is there a way to add some sort of relaxation (in the end both binaries were build for arm64).
2
0
2.4k
Mar ’24
iOS 26 EXC_BREAKPOINT in libmalloc _xzm_xzone_malloc_freelist_outlined during NSData base64 encoding
We are seeing a low-volume but persistent crash on iOS 26 that surfaces inside Foundation's base64 encoder, and we would like to see if and how we could prevent that crash 2026-08-14_10-47-14.9181_-0500-5b74aa117551b30ab7696e1d90c129b97ab1e42f.crash - (nonnull NSString *)pnd_UTF8Base64 { NSData *encodedData = [self dataUsingEncoding:NSUTF8StringEncoding]; if (encodedData == nil || encodedData.length == 0) { return @""; } NSData *safeData = [NSData dataWithBytes:encodedData.bytes length:encodedData.length]; return [safeData base64EncodedStringWithOptions:0]; } Questions: Is our reading correct that _xzm_xzone_malloc_freelist_outlined indicates the freelist was ALREADY corrupted before this allocation (double-free / use-after-free / buffer overflow somewhere else), and that this base64 malloc is merely the first allocation to detect it (a 'canary'), not the cause? Did the iOS 26 xzone allocator add/strengthen freelist integrity checks such that latent corruption that previously went unnoticed now traps here? What is the recommended way to pin down the real corruptor in a shipping app where this reproduces only occasionally on end-user devices (MallocStackLogging, Guard Malloc / libgmalloc, MallocScribble, Address Sanitizer, MallocNanoZone settings)? Are any of these usable/meaningful against the xzone allocator? Is there any process-level or per-allocation API to validate heap integrity that is safe on the xzone allocator (e.g. malloc_zone_check behavior on iOS 26)? Any guidance on interpreting this signature and isolating the root cause would be appreciated. Thanks.
Replies
1
Boosts
0
Views
409
Activity
Aug ’26
Application Hangs with Nested LazyVStack When Accessibility Inspector is Active
Description I've encountered a consistent hang/freeze issue in SwiftUI applications when using nested LazyVStack containers with Accessibility Inspector (simulator) or VoiceOver (physical device) enabled. The application becomes completely unresponsive and must be force-quit. Importantly, this hang occurs in a minimal SwiftUI project with no third-party dependencies, suggesting this is a framework-level issue with the interaction between SwiftUI's lazy view lifecycle and the accessibility system. Reproduction Steps I've created a minimal reproduction project available here: https://github.com/pendo-io/SwiftUI_Hang_Reproduction To Reproduce: Create a SwiftUI view with the following nested LazyVStack structure: struct NestedLazyVStackView: View { @State private var outerSections: [Int] = [] @State private var innerRows: [Int: [Int]] = [:] var body: some View { ScrollView { LazyVStack(alignment: .leading, spacing: 24) { ForEach(outerSections, id: \.self) { section in VStack(alignment: .leading, spacing: 8) { Text("Section #\(section)") // Nested LazyVStack LazyVStack(alignment: .leading, spacing: 2) { ForEach(innerRows[section] ?? [], id: \.self) { row in Text("Section #\(section) - Row #\(row)") .onAppear { // Load more data when row appears loadMoreInner(section: section) } } } } .onAppear { // Load more sections when section appears loadMoreOuter() } } } } } } Enable Accessibility Inspector in iOS Simulator: Xcode → Open Developer Tool → Accessibility Inspector Select your running simulator Enable Inspection mode (eye icon) Navigate to the view and start scrolling Result: The application hangs and becomes unresponsive within a few seconds of scrolling Expected Behavior The application should remain responsive when Accessibility Inspector or VoiceOver is enabled, allowing users to scroll through nested lazy containers without freezing. Actual Behavior The application freezes/hangs completely CPU usage may spike The app must be force-quit to recover The hang occurs consistently and is reproducible Workaround 1: Replace inner LazyVStack with VStack LazyVStack { ForEach(...) { section in VStack { // ← Changed from LazyVStack ForEach(...) { row in ... } } } } Workaround 2: Embed in TabView TabView { NavigationStack { NestedLazyVStackView() // ← Same nested structure, but no hang } .tabItem { ... } } Interestingly, wrapping the entire navigation stack in a TabView prevents the hang entirely, even with the nested LazyVStack structure intact. Questions for Apple Is there a known issue with nested LazyVStack containers and accessibility traversal? Why does wrapping the view in a TabView prevent the hang? Are there recommended patterns for using nested lazy containers with accessibility support? Is this a timing issue, a deadlock, or an infinite loop in the accessibility system? Why that happens? Reproduction Project A complete, minimal reproduction project is available at: https://github.com/pendo-io/SwiftUI_Hang_Reproduction
Replies
8
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0
Views
1.3k
Activity
Jun ’26
accessibilityRespondsToUserInteraction return true on Simulator but false on device
I am seeing a strange issue where NSObject accessibilityRespondsToUserInteraction returns true on Simulator but false on device. Checking the same object on simulator with Accessibility inspector I see the object traits as image so why would it return true in that case? Are there any other way to check the the item might be accessibilityRespondsToUserInteraction OR Clickable beside that property and traits? (Or is it just another bug)
Replies
1
Boosts
0
Views
179
Activity
Jun ’25
Integrating binary inside Framework via SPM
So I will summary an issue one of our clients has asked us on GitHub: https://github.com/pendo-io/pendo-mobile-sdk/issues/233 Project that is a custom framework that uses different SPM packages (one of them is Binary package), we have our main logic inside that framework and we have different targets that use this framework, everything works on the simulator, but running the app on the actual device provokes a crash saying "Binary framework was not found". We have like 20 other SPM packages that work fine, this is the first one we have an issue with. Please note I understand that SPM will not copy paste the Binary for the magic framework as it does for the apps so I suggested to embed it manually. So my question is what the best(easy) way to do it. Please refer to the following issue for more details: https://github.com/pendo-io/pendo-mobile-sdk/issues/233
Replies
0
Boosts
0
Views
228
Activity
Mar ’25
Running dynamically loaded js code in iOS
Hello, We're developing an SDK for iOS and need clarification on Apple's policies regarding the use of JavaScriptCore. Specifically, we want to understand if it's permissible to execute JavaScript code provided by our customers using JavaScriptCore. Our use case is as follows: Our customers will supply JavaScript code snippets, which our SDK will receive as text. The intention is to run these code snippets via JavaScriptCore to present interactive guides or dynamic content to the end-users of the app. Would executing customer-provided JavaScript code in this manner be considered a violation of Apple's App Store guidelines?
Replies
5
Boosts
0
Views
889
Activity
Feb ’25
use of undeclared identifier '$rdi'
I am on M1 (Xcode Version 15.4 (15F31d), MacOS 14.5 (23F79), Simulator IOS 17.4) and as far as I remember printing common usage register was possible. I am not sure why it stopped to work rid, rsi and etc (arg1 arg2 seems like still working).
Replies
4
Boosts
0
Views
1.4k
Activity
Jul ’24
Crash objc_retain_x0
Attaching several crash traces: 2024-02-29_22-48-33.6864_-0600-3f948243e21b4c68d77a38d9cf1cecfdfe2c1565.crash 2024-03-04_15-00-02.9335_-0600-75000cd5acd63ba1434f2ffb3648b97259dddb88.crash 2024-03-05_08-55-47.2097_-0500-f682b25663107ad46f091d65f402f2be31f3f3c6.crash 2024-03-11_08-09-00.4057_-0400-e37d1a635d51afbb67ac38b42dd79c1718a408e8.crash 2024-03-15_16-20-22.6446_-0600-d4ebccf455e8305038ca564a39a5661a1dce6231.crash The final code: - (NSObject*)objectAtIndex:(NSUInteger)index { if (index < self.count) { return [self.embeddedArray objectAtIndex:index]; } else { [PNDErrorReporting reportError:PNDErrorReasonTypeSafeCollectionCrashPrevented message:@"Error msg"]; return nil; } } We subclass NSMutableArray to prevent potential crashes. but we encounter a new crash in our sdk for one of the clients. Also we noticed the stack trace skipped one of the frames (stack calls) in the crash report, in which cases the stack trace wont be identical to the actual code (beside inline)?
Replies
8
Boosts
0
Views
2.5k
Activity
Jun ’24
NSarray crashes with different exceptions from the same place
It seems that that all the crashes are coming from the same place BUT the error is slightly different. Attaching the code that responsible for the crash: static NSString * const kDelimiter = @"#$@"; + (PNDArray *)getObjectsFromData:(NSData *)data { NSString *dataStr = [[NSString alloc] initWithData:data encoding:encoding]; dataStr = [dataStr stringByReplacingOccurrencesOfString:@"\\u0000" withString:@""]; NSArray *components = [dataStr componentsSeparatedByString:kDelimiter]; NSMutableArray *result = [NSMutableArray array]; for (NSString *jsonStr in components) { if (jsonStr != nil && jsonStr.length != 0 && ![jsonStr hasPrefix:kBatchUUID]) { [result addObject:jsonStr]; } } return [PNDArray arrayWithArray:result]; } 2024-04-16_17-15-34.1922_-0600-dfa2faecf702f23e3f6558bea986de4f62851761.crash 2024-04-24_04-56-53.4664_-0500-6b125d3d03b7e497b6be339c2abb52f29658824b.crash 2024-04-25_11-13-53.1326_-0700-bfe370be3eae8d65f465eac714905dd3d13aa665.crash 2024-05-03_11-47-36.6085_-0500-2793587e7ed1c02b0e4334bbc3aa0bd7f7a0cf3d.crash 2024-05-05_10-49-40.5969_-0700-4d86636b0877fceb8c0cdb9586ee16dfb0a9c934.crash
Replies
15
Boosts
0
Views
2.4k
Activity
Jun ’24
Check if NSMicrophoneUsageDescription exists
In our third party SDK we would like to use microphone (as optional feature) in case the hosting app allows it. From the docs requestRecordPermission will crash if no NSMicrophoneUsageDescription exists in the hosting app info.plist. Obviously I don't want to crash the app. I would like to check if the hosting app will allow me to call requestRecordPermission before calling it? Is it possible
Replies
1
Boosts
0
Views
1.1k
Activity
Jun ’24
Install .app file on simulator m1
I have a general question that confusing me. I am on M1 and I can build my app on Xcode (or create an archive) for device. Looking in to derived data I can see Debug-iphones (and simulators) folders, I can get the .app and drag/drop it to the simulator. When trying to run the app the app will crash with error: EXEC 14 Binary with wrong platform I understand that it wasn't build for simulators but rather it was build for devices and there fore the crash, but when thinking about it I dont understand why? (at least theoretically it shouldn't crash as it was build for arm64 ). Inspected the binary with lipo it was build for arm64. Comparing the binaries for simulator and device (with otool) I dont see a lot of difference except the rpath. So how does IOS knows it was build for device and not simulator (wrong platform)? is there a way to add some sort of relaxation (in the end both binaries were build for arm64).
Replies
2
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0
Views
2.4k
Activity
Mar ’24