Re: CFURL crash: multi-threading issue?

Subject: Re: CFURL crash: multi-threading issue?

From: João Pavão <email@hidden>

Date: Tue, 29 Jan 2008 15:45:30 +0000

Delivered-to: email@hidden

Hi,

On the main thread we reach the CFURL stuff when a WebView is initialized. We're also using the Sparkle framework for checking for updates. Sparkle uses NSThread to detach a new thread and then uses a synchronous NSURLConnection to get the list of updates on the detached thread.

We also have another thread that is running permanently. This one is used for running the core of the app and is C++/Qt only. This is all setup from C++/Qt code, that creates this secondary thread using the Qt API, and then calls NSApplicationMain() on the main thread to pass control of it to Cocoa.

Maybe this unconventional setup we have going here is the cause (or the trigger) for this issue. For now, I think I'll experiment with delaying the check for app updates until some time after the app has started to see whether it works around the issue.

Thanks!

João Pavão

On 2008/01/28, at 21:47, Jeff Jenkins wrote:

Hi,

Can you tell me what APIs you are using and on what your threading model is? Specifically, I am wondering what NSURL-family APIs you are using (this is what gets the CFURL-stuff invovled).

Thanks!

-- jrj

Hi,

I've been witnessing some crashes on my project that seem to happen during startup of the app and only when the mac is under some load, like when it has just finished booting and the hard disk is still being hit pretty hard.

I have already searched the list archives and the web and wasn't able to find anything about it.

All crash logs appear to have some very consistent clues, even though the crashes are not happening always at the same place in the code. There are almost always two threads initializing a WebView or CFURL stuff at the same time, the WebView being always on the main thread. Another consistent clue is that a CFURLCache seems to always be involved. I believe CFURL is thread-safe when not sharing instances over different threads. Is it something I am doing wrong, or is it some bug in the frameworks?

Here are some of the crash logs: - <http://trac.softwarelivre.sapo.pt/sapo_msg_mac/attachment/ticket/153/crash%20sapo%20msg%201.txt > - <http://trac.softwarelivre.sapo.pt/sapo_msg_mac/attachment/ticket/153/crash%20sapo%20msg%202.txt > - <http://trac.softwarelivre.sapo.pt/sapo_msg_mac/attachment/ticket/153/SAPO%20Messenger_2008-01-24-104922_Leapfrog-iMac.crash >

Thanks, -- João Pavão
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References:
	>Re: CFURL crash: multi-threading issue? (From: Jeff Jenkins <email@hidden>)