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

Question

My app runs fine but gdb fails to debug it with the following error   gdb  run Starting program   path to app  Unable to find Mach task port for process-id 83767   os kern  failure  0x5     I am on OS X Lion  GDB version is    gdb --version GNU gdb 6 3 50-20050815  Apple version gdb-1752   Sat Jan 28 03 02 46 UTC 2012  Copyright 2004 Free Software Foundation  Inc  GDB is free software  covered by the GNU General Public License  and you are welcome to change it and or distribute copies of it under certain conditions  Type  show copying  to see the conditions  There is absolutely no warranty for GDB   Type  show warranty  for details  This GDB was configured as  x86 64-apple-darwin

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This link had the clearest and most detailed step-by-step to make this error disappear for me.

In my case I had to have the key as a "System" key otherwise it did not work (which not every url mentions).

Also killing taskgated is a viable (and quicker) alternative to having to restart.

I also uninstalled MacPorts before I started this process and uninstalled the current gdb using brew uninstall gdb.

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It works when I change to sudo gdb executableFileName

User · Answer

I followed this tutorial  and everything is OK

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I needed this command to make it work on El Capitan   sudo security add-trust -d -r trustRoot -p basic -p codeSign -k  Library Keychains System keychain   Desktop gdb-cert cer

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On MacOSX lldb needs to be code signed  The Debug and Release builds are set to code sign using a code signing certificate named lldb codesign    If you don t have one yet you will need to  - Launch  Applications Utilities Keychain Access app  - In Keychain Access select the  login  keychain in the  Keychains    list in the upper left hand corner of the window   - Select the following menu item       Keychain Access- gt Certificate Assistant- gt Create a Certificate     - Set the following settings      Name   lldb codesign     Identity Type   Self Signed Root     Certificate Type   Code Signing  - Click Continue - Click Continue - Click Done - Click on the  My Certificates  - Double click on your new lldb codesign certificate - Turn down the  Trust  disclosure triangle      Change          When using this certificate  Always Trust  - Enter your login password to confirm and make it trusted  The next steps are necessary on SnowLeopard  but are probably because of a bug how Keychain Access makes certificates   - Option-drag the new lldb codesign certificate from the login keychain to   the System keychain in the Keychains pane of the main Keychain Access window   to make a copy of this certificate in the System keychain   You ll have to   authorize a few more times  set it to be  Always trusted  when asked  - Switch to the System keychain  and drag the copy of lldb codesign you just   made there onto the desktop  - Switch to Terminal  and run the following   sudo security add-trust -d -r trustRoot -p basic -p codeSign -k  Library Keychains System keychain   Desktop lldb codesign cer  - Right click on the  lldb codesign  certificate in the  System  keychain  NOT    login   but the one in  System    and select  Delete  to delete it from   the  System  keychain  - Reboot - Clean and rebuild lldb and you should be able to debug   That should do it     Note  - lldb is used in mac as gdb

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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

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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

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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

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Here is a really useful guide which solved my problem OSX 10 13 6     Open Keychain Access In the menu  open Keychain Access   Certificate Assistant   Create a certificate Give it a name  e g  gdbc    Identity type  Self Signed Root Certificate type  Code Signing Check  let me override defaults  Continue until it prompts you for   specify a location for     Set Keychain location to System Create a certificate and close assistant  Find the certificate in System keychains  right click it   get info  or just double click it  Expand Trust  set Code signing to always trust Restart taskgated in terminal  killall taskgated Run codesign -fs gdbc  usr local bin gdb in terminal  this asks for the root password

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These instructions work for OSX High Sierra and avoid running gdb as root  yuck    I recently updated from OSX 10 13 2 to 10 3 3   I think this is when gdb 8 0 1  installed w  homebrew  started failing for me    I had difficulty with other people s instructions   After different instructions  everything was a mess  So I started a fresh   I more or less followed these instructions   Clean the mess      brew uninstall --force gdb    This deletes  all  versions of gdb on the machine In Applications -  Utilities -  Keychain Access  I deleted all previous gdb certificates and keys  be sure you know what you re doing here     It s unclear if this is necessary  but since I d buggered up trying to create those certificates and keys using other instructions I eliminated them anyways   I had keys and certificates in both login and system    Now reinstall gdb    brew install gdb Within Keychain Access  go to menu Keychain Access-  Certificate Assistant -  Create a Certificate Check  Let me override defaults  and set     Name   gdb-cert Identity Type  Self Signed Root Certificate Type   Code Signing   X  Let me override defaults     On 1st Certificate Information page     Serial Number   1 Validity Period  days   3650     On 2nd Certificate Information page  I left all fields blank except those already filled in  On Key Pair Information page  I left the defaults    Key Size   2048 Algorithm   RSA     On Key Usage Extension page  I left the defaults checked       X  Include Key Usage Extension  X  This extension is critical Capabilities   X  Signature     On Extended Key Usage Extension page  I left the defaults checked      X  Include Extended Key Usage Extension  X  This extension is critical Capabilities   X  Code Signing     On Basic Constraints Extension Page  nothing was checked  default   On Subject Alternate Name Extension page  I left the default checked and didn t add anything else      X  Include Subject Alternate Name Extension     On Specify a Location for the certificate page  I set     Keychain  System     I clicked Create and was prompted for my password   Back in the Keychain Access app  I went to System and right clicked on gdb-cert and under dropdown menu Trust  I changed all the fields to Always Trust  Rebooted computer  At the Terminal  I ran codesign -s gdb-cert  usr local bin gdb   I entered my password when prompted  At the Terminal  I ran echo  set startup-with-shell off   gt  gt     gdbinit I ran gdb myprogram and then start within the gdb console  Here  I believe  it prompted for me for my password   After that  all subsequent runs  it did not prompt for my password

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This is a weird approach but it worked for me MacOs HighSierra 10 13 3   Install CLion  It comes with gdb  Once run the gdb using Terminal  Copy the gdb program to your usr local bin   No problem of signin  sudo etc

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Following the instructions here Codesign gdb on macOS seemed to resolve this issue  for me  on macOS High Sierra  10 13 3

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

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