On my ubuntu machine, i received this error while starting debugging in qt 5.1 .
Could not attach to the process. Make sure no other debugger traces this process.
Check the settings of
For more details, see /etc/sysctl.d/10-ptrace.conf
This has been reported as a bug in qt project site .
Temporary solution from bug forum
Temporary workaround (note that this introduces security risk to your system, see Ubuntu wiki page linked above for details):
In /etc/sysctl.d/10-ptrace.conf change value of kernel.yama.ptrace_scope to 0. This file is read at startup time so you will need to reboot to apply change.
You can also set ptrace_scope to 0 for current session only (it will revert back to 1 after rebooting) like this:echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope