gdb fails with "Unable to find Mach task port for process-id" error

Question

It works when I change to sudo gdb executableFileName! :)

In Snow Leopard and later Mac OS versions, it isn't enough to codesign the gdb executable.

You have to follow this guide to make it work: http://www.opensource.apple.com/source/lldb/lldb-69/docs/code-signing.txt

The guide explains how to do it for lldb, but the process is exactly the same for gdb.

You need to create a certificate and sign gdb:

• Open application “Keychain Access” (/Applications/Utilities/Keychain Access.app)
• Open menu /Keychain Access/Certificate Assistant/Create a Certificate...
• Choose a name (gdb-cert in the example), set “Identity Type” to “Self Signed Root”, set “Certificate Type” to “Code Signing” and select the “Let me override defaults”. Click “Continue”. You might want to extend the predefined 365 days period to 3650 days.
• Click several times on “Continue” until you get to the “Specify a Location For The Certificate” screen, then set “Keychain to System”.
• If you can't store the certificate in the “System” keychain, create it in the “login” keychain, then export it. You can then import it into the “System” keychain.
• In keychains select “System”, and you should find your new certificate. Use the context menu for the certificate, select “Get Info”, open the “Trust” item, and set “Code Signing” to “Always Trust”.
• You must quit “Keychain Access” application in order to use the certificate and restart “taskgated” service by killing the current running “taskgated” process. Alternatively you can restart your computer.

• Finally you can sign gdb:

  sudo codesign -s gdb-cert /usr/local/bin/ggdb

  sudo ggdb ./myprog

The problem is that you are not logged in as a root user (which you don't want). You need to create a certificate for gdb to be allowed access. Follow this tutorial and you should be good to go...

http://sourceware.org/gdb/wiki/BuildingOnDarwin

If all else fails, just use: sudo gdb executableFileName