How to use MallocStackLogging on the device?

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Here is how I debug APP with malloc stack history on idevice, it’s really complicate, but I have no other way to deal with an auto release pool memory problem.

  1. You need A jailbreak idevice with developer tools installed, then you have gdb.

  2. To enable malloc stack loggin, you need set environment variables MallocStackLoggingNoCompact and MallocStackLogging, we need some trick to do it.

First, we need grant your app root privilege.

 mv -f /User/Application/xxxxxxxxxxxxx/YOUR_APP.app /Application/YOUR_APP.app
 cd /Application
 chown -R root:wheel YOUR_APP.app
 chmod 4755 YOUR_APP.app/YOUR_APP

Rename your program

mv YOUR_APP.app/YOUR_APP   YOUR_APP.app/BACK_UP_NAME

Use a short shell scrip to start your program, so we can keep the env. Save it to YOUR_APP.app/YOUR_APP

#!/bin/bash
export MallocStackLogging=1
export MallocStackLoggingNoCompact=1

exec /Applications/YOUR_APP.app/BACK_UP_NAME

Done.

Just start you app, touching on the icon or use open command, you’ll see a stack log file in /tmp
directory.

Use ps aux | grep YOUR_APP find process id, gdb -p PROCESS_ID attach to the progress, make a breakpoint, try info malloc ADDRESS, malloc history will show up.

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