Solving NVIDIA Driver Issues on Ubuntu 24.04: The `nokaslr` Solution Explained

Many users of Ubuntu 24.04 with NVIDIA graphics cards encounter problems ranging from installation errors to a black screen after system startup. A common and effective solution for these issues is adding the nokaslr kernel parameter. In this article, we explain what's behind this fix and how you can apply it.

What is KASLR and Why Does It Exist?

KASLR stands for Kernel Address Space Layout Randomization. It is a security feature in modern operating systems. Imagine the kernel—the core of the operating system—as a critical fortress. Without KASLR, this fortress is always located at the same, well-known address in memory. Attackers who want to exploit a vulnerability know exactly where to strike.

KASLR randomly changes the kernel's starting address every time the system boots. In other words, the fortress is rebuilt in a different location each time. This makes it significantly harder for attackers to carry out targeted attacks on the kernel because they can no longer predict its memory address.

The Problem: NVIDIA Drivers and KASLR

The proprietary NVIDIA drivers are complex software packages that need to integrate deeply into the system to unlock the full performance of the graphics card. To do this, they must work closely with the kernel.

On Ubuntu 24.04, it appears that in certain configurations, conflicts arise between the memory randomization by KASLR and the NVIDIA driver. The driver "can't find" the kernel at the expected location, which can lead to various errors:

The driver fails to load correctly.
Commands like nvidia-smi fail.
The graphical desktop does not start, often resulting in a black screen.

The Solution: `nokaslr` as a Temporary Workaround

The solution is to disable KASLR. This is done by adding the nokaslr parameter to the kernel's boot options.

Here’s how to do it:

Open the GRUB Configuration File: Start a terminal and enter the following command to open the GRUB configuration file with a text editor. We use nano here, but you can use any other editor like gedit or vim.
```
sudo nano /etc/default/grub
```
Find and Edit the Relevant Line: In the file, look for the line that starts with GRUB_CMDLINE_LINUX_DEFAULT. It usually looks like this:
```
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
```
Add nokaslr: Add nokaslr to the existing options. Make sure to place the new entry inside the quotation marks.
```
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nokaslr"
```
Save and Close the File: Press CTRL + O, followed by Enter, to save the changes. Press CTRL + X to exit the editor.
Update GRUB: For the changes to take effect, you must update GRUB. Enter the following command in the terminal:
```
sudo update-grub
```
Restart Your Computer: After a restart, the kernel will load without KASLR, which in most cases resolves the issues with the NVIDIA driver.

An Important Security Note

Disabling KASLR turns off a key security feature of the kernel. This theoretically increases the risk that certain types of attacks could be successful. For a typical desktop PC, this risk is generally low but should not be ignored.

It is expected that NVIDIA and the Linux community are working on a solution that will make the nokaslr workaround unnecessary in the future. It is therefore advisable to watch for future driver and kernel updates and check if the problem is resolved without nokaslr.

Conclusion

The nokaslr option is an effective workaround to bypass the current incompatibilities between NVIDIA drivers and the Ubuntu 24.04 kernel. The setup is straightforward and, in many cases, resolves the frustrating issues with black screens and non-functional drivers. However, keep the security implications in mind and regularly check if an update makes disabling KASLR obsolete.

Sources: 1 , 2

Solving NVIDIA Driver Issues on Ubuntu 24.04: The nokaslr Solution Explained