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NVIDIA Driver Issues on Ubuntu 24.04: The nokaslr Fix

Fix NVIDIA driver black screens on Ubuntu 24.04 with the nokaslr kernel parameter — what KASLR breaks and how the workaround works.

3 min readflozi00
linuxsystemsnvidiadriversubuntuguide

Many users of Ubuntu 24.04 with NVIDIA graphics cards encounter problems ranging from installation errors to a black screen after system startup. One working fix that circulates for a specific subset of these issues is adding the nokaslr kernel parameter. In this article, we explain what is behind this fix, what it demonstrably solves — and where honest attribution ends.

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 Documented Problem: CUDA HMM and KASLR

The claim that nokaslr fixes NVIDIA driver problems needs careful scoping, because "NVIDIA driver fails on Ubuntu" is a symptom with several unrelated root causes — Secure Boot rejecting the unsigned module, a GSP firmware issue, or an actual kernel interaction. The one conflict that is documented in NVIDIA's own developer forums is between KASLR and CUDA's Heterogeneous Memory Management (HMM): CUDA HMM lets GPUs and CPUs transparently share virtual address spaces, and the randomized kernel memory layout can conflict with CUDA HMM's ability to map and maintain shared GPU/CPU memory references. Reported symptoms include cudaGetDeviceCount() returning Error 802: system not yet initialized, instability, and performance degradation — systems where nvidia-smi lists the GPUs fine but every CUDA initialization fails.

An honest caveat: these reports come from B200-class multi-GPU nodes running recent drivers; this is not a blanket "every Ubuntu 24.04 NVIDIA black screen" fix.

  • Driver loads, but CUDA initialization fails across all contexts (PyTorch, raw CUDA binaries).
  • nvidia-smi succeeds while cudaGetDeviceCount() returns Error 802.
  • Instability or performance degradation after enabling CUDA HMM workloads.

The Solution: nokaslr as a Temporary Workaround

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

Here's how to do it:

  1. Open the GRUB Configuration File: Start a terminal and open the GRUB configuration file with a text editor — nano here, but vim or any other editor works.

    bash
    sudo nano /etc/default/grub

  2. 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"

  3. 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"

  4. Save and Close the File: Press CTRL + O, followed by Enter, to save the changes. Press CTRL + X to exit the editor.

  5. Update GRUB: For the changes to take effect, you must update GRUB. Enter the following command in the terminal:

    bash
    sudo update-grub

  6. Restart Your Computer: After a restart, the kernel will load without KASLR, which resolves the CUDA-HMM/KASLR conflict where that is the actual root cause.

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.

Because this is a community-documented workaround rather than an NVIDIA-published fix, the honest expectation is to re-test on every driver and kernel update: remove nokaslr, reboot, and check whether the issue reappears — rather than assuming a coordinated fix is in flight.

Conclusion

The nokaslr option is an effective workaround for the specific, forum-documented CUDA-HMM/KASLR conflict. It is not a universal cure for every Ubuntu 24.04 NVIDIA failure — check Secure Boot and MOK enrollment first when the module refuses to load at all. The setup is straightforward and, where KASLR is the root cause, resolves the frustrating Error-802-class issues. Keep the security implications in mind and re-check every update whether disabling KASLR is still needed.

Sources: the two primary threads documenting the KASLR–CUDA-HMM conflict and the nokaslr workaround: 1 , 2