Ios 如何诊断碰撞报告

我有一个UIViewController:DFUserChatViewController，它是从DFChatViewController继承的，在DFChatViewController初始化方法中，我有一个navigationItem.LeftBarButtonim和一个backAction方法

- (id)init
{
    self = [super init];
    if (self)
    {
       ...........

       self.navigationItem.leftBarButtonItem = [[[DFBarBackButtonItem alloc] initWithTarget:self action:@selector(backAction:) image:nil] autorelease];
    }
    return self;
}

在DFUserChatViewController中，我覆盖了方法backAction：

#pragma mark - action
-(void)backAction:(id)sender
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    .............any other thing  
    .............
    {
        [self.navigationController popViewControllerAnimated:YES];
    }
}

我使用crashlytics进行崩溃报告，今天我收到了一个崩溃报告

0
Crashed: com.apple.main-thread
EXC_BAD_ACCESS KERN_INVALID_ADDRESS at 0x4000000c
raw
0
libobjc.A.dylib  objc_msgSend + 5
1
DFmyPro     
DFUserChatViewController.m line 349
-[DFUserChatViewController backAction:]
2
UIKit    -[UIApplication sendAction:to:from:forEvent:] + 90
3
UIKit    -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 30
4
UIKit    -[UIControl sendAction:to:forEvent:] + 44
5
UIKit    -[UIControl _sendActionsForEvents:withEvent:] + 374
6
UIKit    -[UIControl touchesEnded:withEvent:] + 590
7
UIKit    -[UIWindow _sendTouchesForEvent:] + 528
8
UIKit    -[UIWindow sendEvent:] + 832
9
DFmyPro 
DFShakeWindow.m line 46
-[DFShakeWindow sendEvent:]
10
UIKit    -[UIApplication sendEvent:] + 196
11
UIKit    _UIApplicationHandleEventQueue + 7098
12   CoreFoundation  __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
13
CoreFoundation   __CFRunLoopDoSources0 + 206
14
CoreFoundation   __CFRunLoopRun + 622
15
CoreFoundation   CFRunLoopRunSpecific + 522
16
CoreFoundation   CFRunLoopRunInMode + 106
17
GraphicsServices     GSEventRunModal + 138
18   UIKit   UIApplicationMain + 1136
19
DFmyPro 
main.m line 15

主要

---

我一次又一次地运行我的应用程序，但没有发现崩溃，我如何知道哪里出了问题

所以，为了确保我理解你。。。第一块代码和后退按钮出口来自DFChatViewController，但第二块代码来自DFUserChatViewController，后者继承自DFChatViewController？您可以发布DFChatViewController的backAction:method吗？DFChatViewController有自己的backAction:method实现，DFUserChatViewController只是覆盖了它