Problem with gdb

[angelopassa]

I have a problem with gdb. I started an ubuntu machine with cpu intel. When in type "run" on gdb it reports this error: "Couldn't get registers: Input/output error."

[kdrag0n]

It looks like Rosetta for Linux doesn't support running debuggers. Neither does QEMU:

(gdb) run
Starting program: /usr/bin/dmesg
warning: Could not trace the inferior process.
warning: ptrace: Function not implemented
During startup program exited with code 127.

Rosetta includes a GDB debug server which you should be able to connect to as a remote debug target, like this:

ROSETTA_DEBUGSERVER_PORT=4040 ls &
gdb ls
target remote :4040

Unfortunately, Rosetta just gets stuck using 100% CPU in a busy-loop when I run it like that.

I don't think there are any good answers here. While I don't think it's an inherent limitation, supporting ptrace + debugging in userspace emulators is hard and it looks like there aren't any Linux ones that implement it fully (yet). Your use case may be better served by apps that run full-blown emulated VMs with QEMU (but obviously at a much larger performance cost due to emulation).

[andrewcrook]

So you are using Ubuntu?
arm64 version and arm64 VM?
using Apples Hypervisor framework ?
installed amd64 (x86_64) versions of software for testing?
and its using Rosetta v2 + setup with bin utils ?

I presume this is correct with orbstacks setup?

You cannot directly run gdb since you would be debugging the rosetta runtime.
So you have to do it through Rosetta via ROSETTA_DEBUGSERVER_PORT

I did read somewhere a security setting in Ubuntu that can stop the attachment of processes so have you tried?

'echo 0 > sudo tee /proc/sys/kernel/yama/ptrace_scope `

Yama is a Linux Security Module that collects system-wide DAC security protections that are not handled by the core kernel itself. This is selectable at build-time with CONFIG_SECURITY_YAMA, and can be controlled at run-time through sysctls in /proc/sys/kernel/yama:
https://www.kernel.org/doc/html/latest/admin-guide/LSM/Yama.html

By default, on Ubuntu, a process can only attach to another process if it has a predefined relationship with it. An example would be a parent process that has started a child process. This is a restriction to ptrace and is valid for non-root users only. It is designed to ensure higher security to malware attacks. The root user can still attach to any process.

This affects unsolicited Dynamic Attachment debugging.

This behavior is defined by the sysctl value in /proc/sys/kernel/yama/ptrace_scope, which is set to 1, by default.

To relax the restriction and allow processes to attach to other processes, this value must be set to 0. This allows processes that have the same user id to attach to each other. Execute the following to remove the restriction:

https://www.microfocus.com/documentation/enterprise-developer/ed80/ED-Eclipse/GUID-C1576E22-D5BC-420C-825D-562A39C7C2DB.html

[kdrag0n]

The debug server does work now. It's not related to the ptrace_scope sysctl.