Unix and Linux Stack Exchange
Unix and Linux Stack Exchange

Questions tagged [user-mode-linux]

For questions involving user-mode Linux (UML), a virtualisation tool which runs a Linux kernel as a user-mode application inside a host. Use this tag for questions about UML itself, using UML, or questions where UML significantly affects the behaviour of the system.

User-mode Linux (UML, not to be confused with Unified Modeling Language) is a virtualisation technique which involves running (modified) Linux kernels as user-mode applications. These modified kernels themselves run a full-blown guest environment, inside the host.

Use this tag for questions:

  • about user-mode Linux itself (how it works, its features etc.) — but do check the UML web site before asking;
  • about problems you’ve run into when trying to use user-mode Linux, specifically;
  • about problems you’re trying to fix where the use of user-mode Linux is (in your opinion) a significant part of the problem, e.g. because it limits what the system can do.
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Why would someone want to run UserMode Linux (UML)

The Linux README states that: Linux has also been ported to itself. You can now run the kernel as a userspace application - this is called UserMode Linux (UML). Why would someone want to do this?
JohnAllen
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How can a user run a program in kernel mode?

Is it possible for a user to run their own program in kernel mode? How could a user accomplish this? What weakness in the system's protection mechanism would they have to bypass? I'm thinking that a user program can switch the mode bit from user…
stevetronix
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2 answers

How to create rootfs for user mode Linux on Fedora 18?

I want to create a rootfs to be used with an UML kernel and be able to use the internet. I was using febootstrap with packages: bash, coreutils, net-tools, iputils. After using febootstrap-supermin-helper I got my rootfs but when trying to boot it…
Peter
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1 answer

Not able to change default group for user with `sudo usermod -g`

I have looked at the questions and answer here at U&L but I still cannot get my default group to change from a user. [red@ws-red-l ~]$ whoami red [red@ws-red-l ~]$ groups yellow green [red@ws-red-l ~]$ sudo usermod -g green red usermod: no…
Red Cricket
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1 answer

User Mode Linux compile fails

I am trying to compile User Mode Linux on a 64 bit machine with defconfig and getting the following error. arch/x86/um/user-offsets.c:1: sorry, unimplemented: code model "large" not supported yet Any idea what this means?
vpillai
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2
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How do I run the usermode linux kernel?

I followed the steps here and compiled the kernel successfully in usermode: https://btrfs.wiki.kernel.org/index.php/Debugging_Btrfs_with_GDB But when I start ./linux in various ways it always gives me a very similar error:…
Blub
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How do I change the home folder for an user used by process sshd?

I'm logged as root. Need to change home folder of another user but when I run usermod -d /path/to/new/home myuser it returns: usermod: user myuser is being used by process xxxx Said process is sshd. What do I do now? I'd rather not having to…
Christopher Francisco
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User mode linux eth0 connected to host tap ethernet device not coming up

I am trying to setup the network between UML instance running on ubuntu as host. UML--eth0-(192.168.0.254) ----------------tap0--(192.168.0.253)--VM But, I am not able to bring the eth0 device in UP state, even after configuring an ip address. UML…
Abhishek Sagar
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1
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Passing a block device to User Mode Linux (UML)

I am trying to test my own DAX file system using User Mode Linux (UML). I can add my file system to the Linux source and compile it for UML. For testing purpose, I need to pass a block device (e.g., a disk) from the host to UML, so that I can mount…
S Liu
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Problems Building Debian Wheezy Inside User Mode Linux

I am building a Debian virtual machine inside UML, but it is hanging. Here is my shell script for the construction: #!/bin/bash # Let's make sure we're updated printf "\nUpdating...\n" apt update apt upgrade # Next let's collect some tools we may…
Sam Vidovich
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1 answer

Adding multiple user accounts on different primary/secondary groups

I am trying to create several user accounts with different groups in an imx6 board. Currently, no users are created in the device. Hence, I see 1000:1000 as my default user:group ID. The scenario I need to implement is as follows: Create two…
radar101
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How to install kali Linux on an external hard disk?

My machine is running MintOs, I want to install kali Linux on my external hard disk. What are the steps to be followed for doing such setup and how to boot kali OS from my external hard disk?
Sumanth Thyagarajan
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user mode linux aborts right away

./linux rootfstype=hostfs mem=64M rw init=/bin/bash Core dump limits : soft - NONE hard - NONE Checking that ptrace can change system call numbers...OK Checking syscall emulation patch for ptrace...OK Checking…
eyeApps LLC
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Linux C/C++ - any way to create a "transparent" SSL/TLS socket?

Normally, in C or C++, to communicate through a SSL/TLS encrypted TCP socket you need to use whatever functions the SSL/TLS provider (OpenSSL, GnuTLS, etc) gives you in order to perform reads & writes, for example: BIO_write, BIO_read, etc. I have a…
Joe
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apt-get failed to fork in UML (user mode Linux)

I'm running a user mode Linux (Linux-3.19.8) for development testing. I'd like to be able to edit files inside the UML. I have some experience with Vim, so I'd prefer that. But unfortunately when I try installing Vim, this happens: root@elk:/#…
Kitalda
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