iPhone app crash logs -- How can I use them to debug my app?

Question

I'm not an expert in programming in general. I can find my way around Objective-C and Xcode and build working apps with no huge problems but when BUGs arise I'm often lost as to where to begin.

My app works fine on the sim but more often-than-is-comfortable it crashes on the device. I looked at the crash log to see if there was any clue to start from, but, the stuff is way over my head. How can I start making use of THIS and future crash logs in debugging? (crash log below)

Incident Identifier: D7E575E3-8447C2B30BD4
CrashReporter Key:   8b86c9231c06465f682da95e93b4542
Process:         ETFanClub [176]
Path:            /var/mobile/Applications/A9FA8-8E24E292AC9/ETFanClub.app/ETFanClub
Identifier:      ETFanClub
Version:         ??? (???)
Code Type:       ARM (Native)
Parent Process:  launchd [1]

Date/Time:       2010-02-07 12:11:10.813 +0900
OS Version:      iPhone OS 3.1.3 (7E18)
Report Version:  104

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x00000000, 0x00000000
Crashed Thread:  0

Thread 0 Crashed:
0   libSystem.B.dylib              0x33b3db2c 0x33aad000 + 592684
1   libSystem.B.dylib              0x33b3db1a 0x33aad000 + 592666
2   libSystem.B.dylib              0x33b3db0e 0x33aad000 + 592654
3   libSystem.B.dylib              0x33b54e34 0x33aad000 + 687668
4   libstdc++.6.dylib              0x33c5c390 0x33bf6000 + 418704
5   libobjc.A.dylib                0x31391898 0x31389000 + 34968
6   libstdc++.6.dylib              0x33c59a84 0x33bf6000 + 408196
7   libstdc++.6.dylib              0x33c59afc 0x33bf6000 + 408316
8   libstdc++.6.dylib              0x33c59c24 0x33bf6000 + 408612
9   libobjc.A.dylib                0x3138fe54 0x31389000 + 28244
10  CoreFoundation                 0x32433bf6 0x3239e000 + 613366
11  CoreFoundation                 0x323b8b12 0x3239e000 + 109330
12  CoreFoundation                 0x323af838 0x3239e000 + 71736
13  ETFanClub                      0x00012648 0x1000 + 71240
14  Foundation                     0x3370fe76 0x336de000 + 204406
15  Foundation                     0x3370fdb4 0x336de000 + 204212
16  CFNetwork                      0x308d6276 0x30882000 + 344694
17  CFNetwork                      0x3088ca38 0x30882000 + 43576
18  CFNetwork                      0x3088c8c8 0x30882000 + 43208
19  CFNetwork                      0x3088c872 0x30882000 + 43122
20  CFNetwork                      0x3088c7f2 0x30882000 + 42994
21  CFNetwork                      0x3088c792 0x30882000 + 42898
22  CoreFoundation                 0x323f53a0 0x3239e000 + 357280
23  CoreFoundation                 0x323f4c18 0x3239e000 + 355352
24  GraphicsServices               0x335051c0 0x33501000 + 16832
25  UIKit                          0x324a6c28 0x324a3000 + 15400
26  UIKit                          0x324a5228 0x324a3000 + 8744
27  ETFanClub                      0x00002df6 0x1000 + 7670
28  ETFanClub                      0x00002d8c 0x1000 + 7564

Thread 1:
0   libSystem.B.dylib              0x33aae488 0x33aad000 + 5256
1   libSystem.B.dylib              0x33ab1064 0x33aad000 + 16484
2   CoreFoundation                 0x323f5002 0x3239e000 + 356354
3   CoreFoundation                 0x323f4c18 0x3239e000 + 355352
4   WebCore                        0x3018c1d4 0x30108000 + 541140
5   libSystem.B.dylib              0x33ad8780 0x33aad000 + 178048

Thread 2:
0   libSystem.B.dylib              0x33aae488 0x33aad000 + 5256
1   libSystem.B.dylib              0x33ab1064 0x33aad000 + 16484
2   CoreFoundation                 0x323f5002 0x3239e000 + 356354
3   CoreFoundation                 0x323f4c18 0x3239e000 + 355352
4   Foundation                     0x33738998 0x336de000 + 371096
5   Foundation                     0x33731ac6 0x336de000 + 342726
6   Foundation                     0x336dfd0e 0x336de000 + 7438
7   libSystem.B.dylib              0x33ad8780 0x33aad000 + 178048

Thread 3:
0   libSystem.B.dylib              0x33ad32c0 0x33aad000 + 156352
1   CoreFoundation                 0x323be7e2 0x3239e000 + 133090
2   libSystem.B.dylib              0x33ad8780 0x33aad000 + 178048

Thread 4:
0   libSystem.B.dylib              0x33b3e6f0 0x33aad000 + 595696
1   libSystem.B.dylib              0x33ae04a8 0x33aad000 + 210088
2   libSystem.B.dylib              0x33adfc6c 0x33aad000 + 207980
3   JavaScriptCore                 0x332c21c4 0x332bb000 + 29124
4   WebCore                        0x306c80dc 0x30108000 + 6029532
5   libSystem.B.dylib              0x33ad8780 0x33aad000 + 178048

Thread 0 crashed with ARM Thread State:
    r0: 0x00000000    r1: 0x00000000      r2: 0x00000001      r3: 0x384e83cc
    r4: 0x00000006    r5: 0x05f0e63c      r6: 0x2ffff0b8      r7: 0x2ffff0c8
    r8: 0x383855c4    r9: 0x0000000a     r10: 0x000181c0     r11: 0x00000000
    ip: 0x00000025    sp: 0x2ffff0c8      lr: 0x33b3db21      pc: 0x33b3db2c
  cpsr: 0x000f0010

Binary Images:
    0x1000 -    0x1cfff +ETFanClub armv6  <a5a4adec19f32b2a6b24066a3282be75> /var/mobile/Applications/BD8A9FA8-0D00-4B40-8339-E8E24E292AC9/ETFanClub.app/ETFanClub
   0x89000 -    0x8afff  dns.so armv6  <957f94410f77a351749ac39d2b4b4abe> /usr/lib/info/dns.so
0x2fe00000 - 0x2fe26fff  dyld armv6  <544395a4b5546114b878d5131a84fd7f> /usr/lib/dyld
0x30005000 - 0x3000ffff  DataDetectorsUI armv6  <f84ebef0dfbdd719da4b52b5732e895f> /System/Library/PrivateFrameworks/DataDetectorsUI.framework/DataDetectorsUI
0x30010000 - 0x30104fff  libiconv.2.dylib armv6  <f3c5cdf74fe386e4169664a48028bb85> /usr/lib/libiconv.2.dylib
0x30108000 - 0x3085bfff  WebCore armv6  <65181be01889192c1252e2535531c99c> /System/Library/PrivateFrameworks/WebCore.framework/WebCore
0x3087d000 - 0x30881fff  IOSurface armv6  <f19a15d8311b851caeba68c1fef33e11> /System/Library/PrivateFrameworks/IOSurface.framework/IOSurface
0x30882000 - 0x308effff  CFNetwork armv6  <58e56341b7a2a491c727a385b871f7b8> /System/Library/Frameworks/CFNetwork.framework/CFNetwork
0x308f0000 - 0x3092efff  CoreText armv6  <fe5639949094efc4d973a1f6457a4e5c> /System/Library/PrivateFrameworks/CoreText.framework/CoreText
0x3092f000 - 0x309dcfff  ImageIO armv6  <572f72dbfb19a2fd37666bb1d58b13cb> /System/Library/PrivateFrameworks/ImageIO.framework/ImageIO
0x309f9000 - 0x30a03fff  libkxld.dylib armv6  <33215da7e582cbc93ad25bf1cdb8ea62> /usr/lib/system/libkxld.dylib
0x30a05000 - 0x30a40fff  CoreTelephony armv6  <98b8ac66b4615a56958655929505c985> /System/Library/PrivateFrameworks/CoreTelephony.framework/CoreTelephony
0x30a66000 - 0x30a76fff  libbsm.0.dylib armv6  <722065615a92c5d0c57395f0aa624b8d> /usr/lib/libbsm.0.dylib
0x30e1a000 - 0x30e20fff  MBX2D armv6  <5246c74334f4daf6c0b876605134baa1> /System/Library/PrivateFrameworks/MBX2D.framework/MBX2D
0x30f72000 - 0x31073fff  libicucore.A.dylib armv6  <a99c2e5d034344c7447a7420db2b36b1> /usr/lib/libicucore.A.dylib
0x3107e000 - 0x3109cfff  libresolv.9.dylib armv6  <c25b840bd418c833ab6c31a29389445a> /usr/lib/libresolv.9.dylib
0x3110c000 - 0x3110dfff  IOMobileFramebuffer armv6  <89abbd5846018f4b74250e8cb09eaf4c> /System/Library/PrivateFrameworks/IOMobileFramebuffer.framework/IOMobileFramebuffer
0x3110e000 - 0x311bbfff  WebKit armv6  <2bf8152a62e6cbc8a219d80489acb0e7> /System/Library/PrivateFrameworks/WebKit.framework/WebKit
0x311bd000 - 0x31267fff  QuartzCore armv6  <5cab4e700e90abef71c1b2b695bd897a> /System/Library/Frameworks/QuartzCore.framework/QuartzCore
0x31389000 - 0x3142cfff  libobjc.A.dylib armv6  <54f0ebeeb9747bf5075f93e2a5043b5e> /usr/lib/libobjc.A.dylib
0x3142f000 - 0x31463fff  Security armv6  <fb2124d1711c8931a7df711d126193d0> /System/Library/Frameworks/Security.framework/Security
0x31464000 - 0x314b1fff  IOKit armv6  <521cb10d7c6fb9ce21936db07a2587bb> /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
0x314b8000 - 0x314f5fff  libCGFreetype.A.dylib armv6  <b299c486f638e82d10939b7c496b7d78> /System/Library/Frameworks/CoreGraphics.framework/Resources/libCGFreetype.A.dylib
0x316c0000 - 0x316c8fff  AVFoundation armv6  <9626256280a896e5a1101dc0b8cb21ac> /System/Library/Frameworks/AVFoundation.framework/AVFoundation
0x318d5000 - 0x318f3fff  AddressBook armv6  <80bdcada8d61624b2bb0796b7155f570> /System/Library/Frameworks/AddressBook.framework/AddressBook
0x318f4000 - 0x3192efff  libvDSP.dylib armv6  <cf9cc6079374718dce29cba9de48b993> /System/Library/PrivateFrameworks/Accelerate.framework/Frameworks/vecLib.framework/libvDSP.dylib
0x31e7f000 - 0x31e95fff  libJapaneseConverter.dylib armv6  <10a062c64d5827c6e0f0486fc210c889> /System/Library/CoreServices/Encodings/libJapaneseConverter.dylib
0x31fb6000 - 0x31fddfff  AppSupport armv6  <db69446acd77981f1d9c968846e4c868> /System/Library/PrivateFrameworks/AppSupport.framework/AppSupport
0x32020000 - 0x32027fff  WebUI armv6  <bb2e1be75e3a51511bf16d54af1fa774> /System/Library/PrivateFrameworks/WebUI.framework/WebUI
0x32028000 - 0x32052fff  MobileQuickLook armv6  <accf1f4b9ad21f4873767c8556f6b48b> /System/Library/PrivateFrameworks/MobileQuickLook.framework/MobileQuickLook
0x3209f000 - 0x320a5fff  liblockdown.dylib armv6  <f18aa1ca3cc98cda954fd821ff88a3ac> /usr/lib/liblockdown.dylib
0x320c7000 - 0x320eafff  libRIP.A.dylib armv6  <a53df8fe2c05c16f671e2502d0d21f60> /System/Library/Frameworks/CoreGraphics.framework/Resources/libRIP.A.dylib
0x320eb000 - 0x320ebfff  vecLib armv6  <c8a08b45effd5eb35a476a969628e52d> /System/Library/PrivateFrameworks/Accelerate.framework/Frameworks/vecLib.framework/vecLib
0x322e7000 - 0x3231bfff  SystemConfiguration armv6  <4b1e9c323f8c973bac2737cdccec8de3> /System/Library/Frameworks/SystemConfiguration.framework/SystemConfiguration
0x3234d000 - 0x32364fff  OpenGLES armv6  <8d075dd39e978efae59c70eeedfd858a> /System/Library/Frameworks/OpenGLES.framework/OpenGLES
0x3239e000 - 0x3244afff  CoreFoundation armv6  <26d25c2c53c05db6e9adc24d5befaa2c> /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation
0x3244b000 - 0x3244bfff  Accelerate armv6  <21e1dc9fad96f0d51afbeb7f7e006aaf> /System/Library/PrivateFrameworks/Accelerate.framework/Accelerate
0x324a3000 - 0x33294fff  UIKit armv6  <4e881f8351712fd798c335af748b5b5f> /System/Library/Frameworks/UIKit.framework/UIKit
0x332bb000 - 0x333b8fff  JavaScriptCore armv6  <41bc769b8c046770bac84eed2b08ff42> /System/Library/PrivateFrameworks/JavaScriptCore.framework/JavaScriptCore
0x333e6000 - 0x334dcfff  libxml2.2.dylib armv6  <a2f276df14b4ded9650dea857293b4e9> /usr/lib/libxml2.2.dylib
0x33501000 - 0x3350cfff  GraphicsServices armv6  <3a4ec1bf23242cddae5f606f0ed38930> /System/Library/PrivateFrameworks/GraphicsServices.framework/GraphicsServices
0x3350d000 - 0x33661fff  AudioToolbox armv6  <31bb7db82eece25ac6742672e3afbe02> /System/Library/Frameworks/AudioToolbox.framework/AudioToolbox
0x336a9000 - 0x336b5fff  CoreVideo armv6  <63d65206a8853262b597f97b3d949f31> /System/Library/PrivateFrameworks/CoreVideo.framework/CoreVideo
0x336de000 - 0x337d6fff  Foundation armv6  <a3612d56db60ccfc998caee19d9805d7> /System/Library/Frameworks/Foundation.framework/Foundation
0x338d0000 - 0x33a8afff  CoreGraphics armv6  <41796502b08a751095dcd2b105d1931c> /System/Library/Frameworks/CoreGraphics.framework/CoreGraphics
0x33a92000 - 0x33a9afff  libgcc_s.1.dylib armv6  <6673f222acee5f3a208169712387862a> /usr/lib/libgcc_s.1.dylib
0x33aa2000 - 0x33aacfff  MobileCoreServices armv6  <805d82b950722ad728d87e0c24089c4b> /System/Library/Frameworks/MobileCoreServices.framework/MobileCoreServices
0x33aad000 - 0x33bd3fff  libSystem.B.dylib armv6  <0373fd64e915a17160732b29d343f95f> /usr/lib/libSystem.B.dylib
0x33bf6000 - 0x33c60fff  libstdc++.6.dylib armv6  <a35cfd59eee09893fbab57794ad7cbaf> /usr/lib/libstdc++.6.dylib
0x33c61000 - 0x33c6dfff  DataDetectorsCore armv6  <fd18ffc95012b76c319875bedd99eb43> /System/Library/PrivateFrameworks/DataDetectorsCore.framework/DataDetectorsCore
0x33da7000 - 0x33e01fff  libsqlite3.dylib armv6  <61513660cb3e21b47ccbf5407e0efae5> /usr/lib/libsqlite3.dylib
0x33f83000 - 0x34096fff  libmecab_em.dylib armv6  <a3c3e3dc97dc2aebad18b5a3c9673df0> /usr/lib/libmecab_em.dylib
0x340e2000 - 0x3413dfff  CoreAudio armv6  <71fb4de4976308c0a3f86d127e46472b> /System/Library/Frameworks/CoreAudio.framework/CoreAudio
0x3430e000 - 0x3431cfff  libz.1.dylib armv6  <7a06dbf4af39c5b548306c7fb8ffcf0b> /usr/lib/libz.1.dylib
0x3439e000 - 0x343a7fff  SpringBoardServices armv6  <f13747f4598b0f4b1442877adc75de5a> /System/Library/PrivateFrameworks/SpringBoardServices.framework/SpringBoardServices
0x343a8000 - 0x343a9fff  liblangid.dylib armv6  <f8f20663988ec129b14a4e5a06e1ab0d> /usr/lib/liblangid.dylib
0x343ab000 - 0x343acfff  CoreSurface armv6  <f27efe4047d6b4319bc01edb9007a789> /System/Library/PrivateFrameworks/CoreSurface.framework/CoreSurface

Answer 1

If you have the very same build still available, run it under GDB and set a breakpoint at 0x00012648, which is the last bit of "your" code in the backtrace.

Then run it, find out where in the source that address is, and puzzle out ways it could possibly crash from there. Given that it's crashing in CoreFoundation, you're probably passing an invalid pointer to a CF routine. Chances are that it's already been freed, or never allocated.

Answer 2

When apps crash on the device, the device isn't aware of the codebase, and the identifiers you used (variable names, method names, etc). So, instead of giving you friendly-looking method names and line numbers that crashes occured on, it can only give you the relevant memory addresses.

I believe there are tools to help you reverse the memory addresses to something recognizable. See this Google search from a similar question.

Answer 3

View your crash log using Organizer and it should not look nearly so mysterious. There are tools to interpret the crash logs from other people running on other devices, but you don't need to jump through hoops to decode ones on your own device when your app crashes.

You need to be running the most recently compiled version of your application on your device in order for XCode to be able to decode the symbols for you.