iphone - 奇怪的崩溃并显示消息 "Attempted to dereference garbage pointer"

Question

我的应用程序是 ARC abide 应用程序，但我仍然看到多次崩溃，并在崩溃报告中显示消息“尝试取消引用垃圾指针”。它们很难诊断。

我的问题是，为什么即使我们处于 ARC 上，应用程序也会因为内存问题而崩溃，并且我们无法使用相同的步骤重现它。如何解决此类崩溃问题？

一个这样的崩溃报告如下:

CrashReporterKey: 896d0c8676c0e02eb292865a654825359de4d427 HardwareModel: iPod4,1 Version: 5510 (3.0.0) OSVersion: iPhone OS 6.1.3 (10B329) Date/Time: 2013-08-15 09:50:51.000 -0700 FirmwareVersion: 2.27.0 Report Version: 104

Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x31fd4078 Crashed Thread: 0

Thread 0 name: Dispatch queue: com.apple.main-thread Thread 0 Crashed: 0 libobjc.A.dylib 0x3b1ac5b0 objc_msgSend + 16 1 UIKit 0x3533c350 0x35338000 + 17232 2 UIKit 0x3533b6c8 0x35338000 + 14024 3
UIKit 0x3533b118 0x35338000 + 12568 4
GraphicsServices 0x3702d5a0 0x37027000 + 26016 5
GraphicsServices 0x3702d1d0 0x37027000 + 25040 6
CoreFoundation 0x33508170 0x33471000 + 618864 7
CoreFoundation 0x33508110 0x33471000 + 618768 8
CoreFoundation 0x33506f98 0x33471000 + 614296 9
CoreFoundation 0x33479eb8 CFRunLoopRunSpecific + 352 10 CoreFoundation 0x33479d48 CFRunLoopRunInMode + 104 11 GraphicsServices 0x3702c2e8 GSEventRunModal + 72 12 UIKit 0x3538f300 UIApplicationMain + 1120 13 MyApp 0x000a8e58 main + 20

Thread 1 name: Dispatch queue: com.apple.libdispatch-manager Thread 1: 0 libsystem_kernel.dylib 0x3b69f648 kevent64 + 24 1
libdispatch.dylib 0x3b5cadf8 0x3b5c7000 + 15864

Thread 2 name: WebThread Thread 2: 0 WebCore
0x39503560 0x3945d000 + 681312 1 WebCore
0x394e7f90 0x3945d000 + 569232 2 WebCore
0x394e2788 0x3945d000 + 546696 3 WebCore
0x396ca8a8 _ZN7WebCore11FrameLoader16detachFromParentEv + 64 4
WebKit 0x39e12618 0x39d8d000 + 546328 5
WebCore 0x394699c8 0x3945d000 + 51656 6
WebKit 0x39e12490 0x39d8d000 + 545936 7
WebKit 0x39e18570 0x39d8d000 + 570736 8
WebKit 0x39e184a8 0x39d8d000 + 570536 9
WebCore 0x394fb850 0x3945d000 + 649296 10 CoreFoundation 0x33508680 0x33471000 + 620160 11 CoreFoundation 0x33507ee8 0x33471000 + 618216 12 CoreFoundation 0x33506cb0 0x33471000 + 613552 13 CoreFoundation 0x33479eb8 CFRunLoopRunSpecific + 352 14 CoreFoundation 0x33479d48 CFRunLoopRunInMode + 104 15 WebCore 0x39467500 0x3945d000 + 42240 16 libsystem_c.dylib 0x3b608310 0x3b5f7000 + 70416

Thread 3 name: CommRunLoop Thread Thread 3: 0
libsystem_kernel.dylib 0x3b6af6a4 __semwait_signal + 24 1
Foundation 0x33decc60 0x33d99000 + 343136 2
MyApp 0x002be680 -[CommRunLoop runLoopThread:] + 504 3 Foundation 0x33e49e80 0x33d99000 + 724608 4 libsystem_c.dylib 0x3b608310 0x3b5f7000 + 70416

Thread 4 name: com.apple.CFSocket.private Thread 4: 0
libsystem_kernel.dylib 0x3b6af594 select$DARWIN_EXTSN + 20 1 libsystem_c.dylib 0x3b608310 0x3b5f7000 + 70416

Thread 5: 0 libsystem_kernel.dylib 0x3b6af6a4 __semwait_signal + 24 1 Foundation 0x33decc60 0x33d99000 + 343136 2 MyApp 0x00333580 -[KSCrashDeadlockMonitor runMonitor] + 244 3 Foundation 0x33e49e80 0x33d99000 + 724608 4 libsystem_c.dylib
0x3b608310 0x3b5f7000 + 70416

Thread 6 name: KSCrash Exception Handler (Secondary) Thread 6: 0
libsystem_kernel.dylib 0x3b69eeb4 mach_msg_trap + 20 1
MyApp 0x0032f710 ksmachexc_i_handleExceptions + 124 2 libsystem_c.dylib 0x3b608310 0x3b5f7000 + 70416

Thread 7 name: KSCrash Exception Handler (Primary) Thread 7:

Thread 8 name: com.apple.NSURLConnectionLoader Thread 8: 0
libsystem_kernel.dylib 0x3b69eeb4 mach_msg_trap + 20 1
CoreFoundation 0x33508040 0x33471000 + 618560 2
CoreFoundation 0x33506da0 0x33471000 + 613792 3
CoreFoundation 0x33479eb8 CFRunLoopRunSpecific + 352 4 CoreFoundation 0x33479d48 CFRunLoopRunInMode + 104 5 Foundation 0x33dc63d0 0x33d99000 + 185296 6 Foundation 0x33e49e80 0x33d99000 + 724608 7
libsystem_c.dylib 0x3b608310 0x3b5f7000 + 70416

Thread 9 name: JavaScriptCore::BlockFree Thread 9: 0
libsystem_kernel.dylib 0x3b6af08c __psynch_cvwait + 24 1
libsystem_c.dylib 0x3b600aa0 pthread_cond_timedwait + 40 2 JavaScriptCore 0x37422c70 _ZN3WTF15ThreadCondition9timedWaitERNS_5MutexEd + 104 3 JavaScriptCore 0x37534550 0x373c7000 + 1496400 4
JavaScriptCore 0x37546fa8 0x373c7000 + 1572776 5
libsystem_c.dylib 0x3b608310 0x3b5f7000 + 70416

Thread 10 name: Dispatch queue: com.apple.root.background-priority Thread 10: 0 MyApp 0x00320a18 +[KSCrashReportFilterAppleFmt filterWithReportStyle:] + 0 1 libdispatch.dylib 0x3b5c9118 0x3b5c7000 + 8472 2
libdispatch.dylib 0x3b5d7258 0x3b5c7000 + 66136 3
libdispatch.dylib 0x3b5d73b8 0x3b5c7000 + 66488 4
libsystem_c.dylib 0x3b5fda10 0x3b5f7000 + 27152

Thread 11: 0 libsystem_kernel.dylib 0x3b6afd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3b5fda10 0x3b5f7000 + 27152

Thread 12: 0 libsystem_kernel.dylib 0x3b6afd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3b5fda10 0x3b5f7000 + 27152

Thread 13: 0 libsystem_kernel.dylib 0x3b6afd98 __workq_kernreturn + 8 1 libsystem_c.dylib 0x3b5fda10 0x3b5f7000 + 27152

Thread 0 crashed with ARM Thread State: r0: 0x1fd2a130 r1: 0x357e82c0 r2: 0x1fd3a6d0 r3: 0x20a8a4a0 r4: 0x31fd4070 r5: 0x20a8a4a0 r6: 0x2fd59a10 r7: 0x2fd599f8 r8: 0x20a8af20 r9: 0x0d5fa0b0 r10: 0xbecb6c00 r11: 0x1fd3a6d0 ip: 0x3bb2bd64 sp: 0x2fd599c8 lr: 0x355abb97 pc: 0x3b1ac5b0 cpsr: 0x20000030

Extra Information:

Stack Dump (0x2fd599a0-0x2fd59a18):

A8B4BC3B209FF240B499D52FADD81A3BA8B4BC3BC099D52F45D91A3BD0A6D31FC899D52FF1D01B3BA0A4A820D0A6D31F000000000020B23F00000000806DD9BF00000000E073ECBF0000000000000000009F63BF209FF240789AD52F51C3333500000000806DD9BF00000000E073ECBFDA1B7C21209FF240

Notable Addresses: { "r1": { "address": 897483456, "type": "string", "value": "accelerometer:didAccelerate:" }, "r11": { "address": 533964496, "class": "UIAccelerometer", "ivars": { "_delegate": { "address": 533897520, "type": "unknown" }, "_updateInterval": 0.1 }, "type": "objc_object" }, "r2": { "address": 533964496, "class": "UIAccelerometer", "ivars": { "_delegate": { "address": 533897520, "type": "unknown" }, "_updateInterval": 0.1 }, "type": "objc_object" }, "r3": { "address": 547923104, "class": "UIAcceleration", "ivars": { "timestamp": 76274, "x": 0.0708008, "y": -0.397308, "z": -0.889145 }, "type": "objc_object" }, "r5": { "address": 547923104, "class": "UIAcceleration", "ivars": { "timestamp": 76274, "x": 0.0708008, "y": -0.397308, "z": -0.889145 }, "type": "objc_object" }, "r8": { "address": 547925792, "class": "__NSCFType", "ivars": {}, "type": "objc_object" }, "stack@0x2fd599a0": { "address": 1002222760, "class": "UIAcceleration", "type": "objc_class" }, "stack@0x2fd599b0": { "address": 1002222760, "class": "UIAcceleration", "type": "objc_class" }, "stack@0x2fd599bc": { "address": 533964496, "class": "UIAccelerometer", "ivars": { "_delegate": { "address": 533897520, "type": "unknown" }, "_updateInterval": 0.1 }, "type": "objc_object" }, "stack@0x2fd599c8": { "address": 547923104, "class": "UIAcceleration", "ivars": { "timestamp": 76274, "x": 0.0708008, "y": -0.397308, "z": -0.889145 }, "type": "objc_object" }, "stack@0x2fd599cc": { "address": 533964496, "class": "UIAccelerometer", "ivars": { "_delegate": { "address": 533897520, "type": "unknown" }, "_updateInterval": 0.1 }, "type": "objc_object" } }

CrashDoctor Diagnosis: Attempted to dereference garbage pointer 0x31fd4078.

Answer 1

即使您使用 ARC，仍然有可能编写有错误的代码——这并不神奇，而且仍然有规则。在这种情况下，尝试在 Xcode 中运行应用程序的调试版本并打开“NSZombies”。这样做的作用是，每次您的应用程序尝试释放一个对象时，Objective-C 都会将其替换为 NSZombie 对象，当您尝试使用它时(尝试使用该对象)，该对象将提供更有用的错误消息取消引用垃圾指针，就像你愚蠢的 CrashDoctor 告诉你的那样)。