Re: Debugging objc_msg errors
Re: Debugging objc_msg errors
- Subject: Re: Debugging objc_msg errors
- From: "Sean McBride" <email@hidden>
- Date: Wed, 14 Jan 2009 18:21:56 -0500
- Organization: Rogue Research Inc.
On 1/14/09 2:33 PM, Greg Parker said:
>On Jan 14, 2009, at 11:18 AM, Jeff Johnson wrote:
>> On Jan 14, 2009, at 1:04 PM, John Nairn wrote:
>>> I occasionally get difficult-to-debug crashes where that last thing
>>> in the crash log is a message being sent, which ends up being a
>>> message sent to an object that has been released (I think it is
>>> objc_msg, but I am not looking at a crash log now). These happen
>>> much more often in Leopard than in Tiger.
>>>
>>> Since I have many messages going to many objects, it can take me a
>>> long time to track these problems down (in one case several weeks).
>>> I am fairly certain it is not a notification message because I also
>>> remove objects as observers before they are deallocated. Is there a
>>> debugging tool that can provide more information about what message
>>> was sent to what object at the time of the crash?
>>
>> See the following for a good tutorial:
>>
>> http://www.sealiesoftware.com/blog/archive/2008/09/22/
>objc_explain_So_you_crashed_in_objc_msgSend.html
>
>That will help you extract info from the crash log itself.
Not to hijack this thread, but... anyone know what objc_msgSend_fixup
is? Recently I've seen a lot of these types of crashes in my (64bit, GC) app.
Thread 0 Crashed:
0 libobjc.A.dylib 0x00007fff809bbcf2
_objc_fixupMessageRef + 39
1 libobjc.A.dylib 0x00007fff809bdc7f objc_msgSend_fixup + 119
2 com.apple.CoreFoundation 0x00007fff82b798b7
__CFMachPortPerform + 119
3 com.apple.CoreFoundation 0x00007fff82b9b3ac
CFRunLoopRunSpecific + 3516
4 com.apple.HIToolbox 0x00007fff80548da2
RunCurrentEventLoopInMode + 278
5 com.apple.HIToolbox 0x00007fff80548bd8
ReceiveNextEventCommon + 322
6 com.apple.HIToolbox 0x00007fff80548a83
BlockUntilNextEventMatchingListInMode + 79
7 com.apple.AppKit 0x00007fff80da93b0 _DPSNextEvent + 603
8 com.apple.AppKit 0x00007fff80da8cf1 -[NSApplication
nextEventMatchingMask:untilDate:inMode:dequeue:] + 136
9 com.apple.AppKit 0x00007fff80da2a84 -[NSApplication
run] + 455
10 com.apple.AppKit 0x00007fff80d6f83c NSApplicationMain + 373
--
____________________________________________________________
Sean McBride, B. Eng email@hidden
Rogue Research www.rogue-research.com
Mac Software Developer Montréal, Québec, Canada
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