Crash using dispatch I/O channel in URLProtocol

Originator:green
Number:rdar://16902536 Date Originated:13-May-2014
Status:Open Resolved:
Product:OS X SDK Product Version:
Classification: Reproducible:Always
 
Summary:
Using a dispatch I/O channel to implement a URLProtocol causes memory corruption if the I/O channel is released before the URLProtocol is deallocated.

Steps to Reproduce:
Run the attached Xcode project on OS X 10.9.

Note: Enabling the "Guard Malloc" configuration makes the crash happen reliably instead of randomly.

Expected Results:


Actual Results:


Version:
Xcode 5.1 on OS X 10.9 or iOS 7

Notes:


Configuration:
It happens in the OS X 10.9 SDK and the iOS 7 SDK.

Attachments:
'ConnectionCrash.zip' was successfully uploaded.

Comments

Workaround

The workaround is to store the I/O channel as an ivar of the NSURLProtocol subclass. It's still ok to close the channel, just not to release the reference to it until the URLProtocol is deallocated.

By green at May 13, 2014, 9:09 p.m. (reply...)

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