Re: Mysterious crash in objc_msgSend in GC app
Re: Mysterious crash in objc_msgSend in GC app
- Subject: Re: Mysterious crash in objc_msgSend in GC app
- From: Bill Bumgarner <email@hidden>
- Date: Tue, 27 Oct 2009 10:48:31 -0700
On Oct 27, 2009, at 10:43 AM, Sean McBride wrote:
> Occasionally, my GC app crashes in objc_msgSend with none of my code in
> the backtrace. This only happens to customers; I've never caught it in gdb.
>
> I've read through Greg's awesome "So you crashed in objc_msgSend()"
> article, but I still don't have a clue. :(
>
> I'm able to determine that the selector was from libobjc.A.dylib but I
> don't know which (the uuid from dwarfdump does not match mine).
>
> I guess I'm hoping this backtrace looks familiar to someone out there... :)
Look at the argument registers (see Greg's Awesome Article) and see if any of 'em point to a hole in or very near the list of dylibs.
The most common cause for a crash like this has been improper unloading of a bundle. There still exists an instance of one of the classes in the bundle (or a reference to one of the classes or a constant NSString) and the messenger is crashing trying to execute a method on said object/class.
The other possibility, of course, is memory corruption. Something stomping on the isa of an instance will cause a crash that looks a lot like that one.
b.bum
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden