[0.7.1] Persistent Segmentation Faults Via `./root-vconsole`

Mar 10, 2025 by ADMIN 61 views

Introduction

In this article, we will explore the issue of persistent segmentation faults when using the ./root-vconsole tool to interface with a Playbit instance via a host machine. The segmentation faults prevent building ports and halt possible changes to existing ports or adding new ports.

Description

Multiple binary commands trigger seg faults when using ./root-vconsole to interface with a Playbit instance via a host machine. Currently, these seg faults (1) prevent building ports and (2) halt possible changes to existing ports, or adding new ports.

The offending binary commands outlined here are:

(a) git clone (using multiple protocols) (b) ssh-keygen (c) tools/pbuild ports/$PORT

There may be other problematic binaries, but these are the immediate speed bumps encountered when attempting to use pb-src tooling and ports.

Steps to Reproduce

Step 1: Set up `pb-src` for Development

Follow the instructions outlined in README.md to set up pb-src for development using git clone (via HTTPS, but other protocols reproduce as well):

$ curl -L#O https://github.com/playbit/pb-src/raw/refs/heads/main/tools/root-vconsole
$ chmod +x root-vconsole
$ ./root-vconsole
Connecting to Playbit root system console...
Press RETURN if you don't see a prompt. Press ctrl-Q to end session.
Set terminal size with: stty rows 38 cols 80
$ git clone https://github.com/playbit/pb-src.git

Step 2: Generate an SSH Key

Attempt to generate an SSH key:

$ ssh-keygen -t ed25519 -C "email@example.com"

Step 3: Build a Port

Since git clone-ing on the Playbit instance isn't an option, we...

On host machine, connect to our running Playbit instance:

$ curl -L#O https://github.com/playbit/pb-src/raw/refs/heads/main/tools/root-vconsole
$ chmod +x root-vconsole
$ ./root-vconsole
Connecting to Playbit root system console...
Press RETURN if you don't see a prompt. Press ctrl-Q to end session.
Set terminal size with: stty rows 38 cols 80

On host machine, in ~, clone pb-src: cd ~ && git clone https://github.com/playbit/pb-src.git
On host machine, tarball pb-src: tar -czf pb-src.tar.gz pb-src
On Playbit instance (via .root-vconsole), in ~, copy tarball from host machine to Playbit instance, unzip, and navigate to pb-src: cd ~ && cp /vhost/pb-src.tar.gz ~ && tar -xf pb-src.tar.gz && cd pb-src
Attempt to build port e.g. curl: tools/pbuild ports/curl

Expected Behavior

Follow the instructions outlined in README.md to set up pb-src for development and successfully build ports:

$ curl -L#O https://github.com/playbit/pb-src/raw/refs/heads/main/tools/root-vconsole
$ chmod +x root-vconsole
$ ./root-vconsole
Connecting to Playbit root system console...
Press RETURN if you don't see a prompt. Press ctrl-Q to end session.
Set terminal size with: stty rows 38 cols 80
$ git clone https://github.com/playbit/pb-src.git
$ cd pb-src
...
$ tools/pbuild ports/curl
checking sources ...
building ports/libc ...
...
building ports/curl: OK /var/pbuild/ports/curl.ARCH/out
$ /var/pbuild/ports/curl.$(uname -m)/out/distroot/bin/curl --version
curl 8.7.1 ...

Actual Behavior

`git clone` & `ssh-keygen` Seg Faults

via HTTPS:

~ $ git clone https://github.com/jthodge/pb-src.git
Cloning into 'pb-src'...
error: git-remote-https died of signal 11

via SSH, generating SSH key:

~ $ git clone git@github.com:jthodge/pb-src.git
Cloning into 'pb-src'...
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
~ $ ssh-keygen -t ed25519 -C "taylor@example.com"
Segmentation fault

via git Protocol:

~ $ git clone git://github.com/jthodge/pb-src.git
Cloning into 'pb-src'...
fatal: unable to connect to github.com:
github.com[0: 140.82.116.3]: errno=Connection refused

Shallow clone, attempting to reduce memory usage:

~ $ git clone --depth 1 https://github.com/jthodge/pb-src.git
Cloning into 'pb-src'...
error: git-remote-https died of signal 11

`pbuild` Seg Faults

pb-src $ tools/pbuild ports/curl
building  OK /var/pbuild/ports/libc.aarch64/out/distroot 11.…
building  OK /var/pbuild/ports/libunwind.aarch64/out/distroot 132.…
building  OK /var/pbuild/ports/make.aarch64/out/distroot 252.…
building  OK /var/pbuild/ports/patch.aarch64/out/distroot 476.…
building  …Segmentation fault

pb-src $ tools/pbuild ports/less
 …
building  …Segmentation fault

pb-src $ tools/pbuild ports/gvim
 …
building  …Segmentation fault

Logs

Nothing immediately stands out to me in the usual suspects e.g. syslog/system.log, dmesg, or crash dumps. Also, couldn't locate any core dumps or application-specific logs. But perhaps I'm overlooking something?

I also checked acpid.log[^3], auth.log[^4], and boot.log[^5] to be thorough, but nothing stood out there either.

As requested in root-vconsole:

➜ bash -x ./root-vconsole
+ set -eo pipefail
+ case "$(uname -s)" in
++ uname -s
+ SOCKFILE='/Users/jth/Library/Application Support/Playbit/vconsole0.sock'
+ '[' 0 -gt 0 ']'
+ command -v socat
++ realpath '/Users/jth/Library/Application Support/Playbit/vconsole0.sock'
+ SOCKFILE='/Users/jth/Library/Application Support/Playbit/vconsole0.sock'
+ '[' '!' -S '/Users/jth/Library/Application Support/Playbit/vconsole0.sock' ']'
+ SOCAT_GREETING=
+ STTY_CMD=
++ stty size
+ TERMSIZE='58 159'
+ '[' -n '58 159' ']'
+ STTY_CMD='stty rows 58 cols 159'
+ SOCAT_GREETING='stty rows 58 cols 159; '
++ printf '\n'
+ SOCAT_GREETING='stty rows 58 cols 159; export TERM='\''xterm-ghostty'\'''
+ export SOCAT_GREETING
+ echo 'Connecting to Playbit root system console...'
Connecting to Playbit root system console...
+ echo 'Press RETURN if you don'\''t see a prompt. Press ctrl-Q to end session.'
Press RETURN if you don't see a prompt. Press ctrl-Q to end session.
+ '[' -z 'stty rows 58 cols 159' ']'
+ echo 'Set terminal size with: stty rows 58 cols 159'
Set terminal size with: stty rows 58 cols 159
+ exec socat -g -t0.1 -,escape=0x11,rawer,icanon=0 'unix-connect:/Users/jth/Library/Application Support/Playbit/vconsole0.sock,nonblock,escape=0x11'

dmesg[^6]:

~ $ dmesg | grep -i "sigsegv\|segfault\|fault\|segmentation"
[    0.000061] pid_max: default: 32768 minimum: 301
[    0.050408] iommu: Default domain type: Translated
[    0.060600] PCI: CLS 0 bytes, default 64
[    0.094802] virtio_blk virtio5: 8/0/0 default/read/poll queues
[    0.096971] virtio_blk virtio6: 8/0/0 default/read/poll queues

system.log[^7]:

~ $ cat /var/log/system.log | grep -i "sigsegv\|segfault\|fault\|segmentation"
~ $

Crash dumps:

~ $ ls -la /var/crash
total 0
drwxr-xr-x    1 root     root             0 Jan 28 07:04 .
drwxr-xr-x    1 root     root            44 Mar  9 20<br/>
**Q&A: Persistent Segmentation Faults via `./root-vconsole`**
=====================================================

**Q: What is a segmentation fault?**
--------------------------------

A: A segmentation fault is a type of error that occurs when a program attempts to access a memory location that it is not allowed to access. This can happen when a program tries to read or write to a memory location that is outside of its allocated memory space.

**Q: What is the `./root-vconsole` tool?**
-----------------------------------------

A: The `./root-vconsole` tool is a command-line interface that allows users to interact with a Playbit instance via a host machine. It provides a way to access the Playbit root system console and perform various tasks such as building ports and managing the system.

**Q: What are the symptoms of a segmentation fault in `./root-vconsole`?**
-------------------------------------------------------------------

A: The symptoms of a segmentation fault in `./root-vconsole` include:

* The program crashes or terminates unexpectedly
* An error message is displayed indicating a segmentation fault
* The program may produce a core dump file, which can be used to diagnose the issue

**Q: What are the possible causes of a segmentation fault in `./root-vconsole`?**
-------------------------------------------------------------------------

A: The possible causes of a segmentation fault in `./root-vconsole` include:

* Memory corruption or allocation errors
* Incorrect use of pointers or memory management functions
* Bugs in the `./root-vconsole` code or dependencies
* Conflicts with other system libraries or programs

**Q: How can I diagnose a segmentation fault in `./root-vconsole`?**
----------------------------------------------------------------

A: To diagnose a segmentation fault in `./root-vconsole`, you can:

* Check the error message or core dump file for clues about the issue
* Use debugging tools such as `gdb` or `lldb` to examine the program's memory and stack
* Review the `./root-vconsole` code and dependencies for potential bugs or issues
* Test the program with different inputs or scenarios to reproduce the issue

**Q: How can I prevent segmentation faults in `./root-vconsole`?**
----------------------------------------------------------------

A: To prevent segmentation faults in `./root-vconsole`, you can:

* Use memory-safe programming practices such as bounds checking and memory allocation
* Avoid using deprecated or insecure functions
* Keep the `./root-vconsole` code and dependencies up to date and secure
* Test the program thoroughly with different inputs and scenarios

**Q: What are the consequences of a segmentation fault in `./root-vconsole`?**
-------------------------------------------------------------------------

A: The consequences of a segmentation fault in `./root-vconsole` can include:

* Data loss or corruption
* System instability or crashes
* Security vulnerabilities or exploits
* Performance degradation or slowdowns

**Q: How can I recover from a segmentation fault in `./root-vconsole`?**
----------------------------------------------------------------

A: To recover from a segmentation fault in `./root-vconsole`, you can:

* Restart the program or system
* Restore a backup or previous version of the program
* Rebuild or reinstall the program and dependencies
* Seek assistance from a developer or support team

**Q: What are the best practices for debugging and troubleshooting segmentation faults in `./root-vconsole`?**
----------------------------------------------------------------------------------------------------------------

A: The best practices for debugging and troubleshooting segmentation faults in `./root-vconsole` include:

* Using debugging tools and techniques such as `gdb` or `lldb`
* Reviewing the program's code and dependencies for potential issues
* Testing the program with different inputs and scenarios
* Keeping the program and dependencies up to date and secure
* Seeking assistance from a developer or support team when necessary.