linux 6.15-rc4 : une mise à jour pour résoudre les crashes du noyau sur les systèmes 32 bits avec trop de mémoire vive

Linux 6.15-rc4: An update to resolve kernel crashes on 32-bit systems with too much RAM

by

In 2025, Linux kernel stability remains a crucial aspect for administrators, particularly on older or limited architectures. The recently released version 6.15-rc4marks an important milestone by providing targeted fixes for 32-bit systems experiencing memory management issues exceeding 4 GB. Developers have undertaken a major overhaul of the code related to HIGHMEM management, significantly reducing the risk of crashes on these configurations. The rise of distributions such as Ubuntu and Debian continues to fuel this need for updates, even for older or specialized devices. Fixing these bugs, while technical, is essential to ensure stability, particularly in professional or embedded environments where kernel reliability is a key issue. Memory Management Challenges in the Linux Kernel for 32-Bit Systems

Historically, Linux has been built on compatibility with 32-bit architectures, which was vital for deploying servers or sophisticated devices like workstations a decade ago. However, with the steady rise in RAM in modern systems—some using up to 64 GB—the limit imposed by the 32-bit architecture is becoming a critical challenge. This results in an increased risk of crashes when the kernel attempts to manage more than 4 GB of RAM, a threshold traditionally considered a practical ceiling. Linux version 6.15-rc4 illustrates this issue by specifically correcting the management of “high memory.”

» within the source code, which avoids overloading the kernel as soon as a system approaches this limit. Progress towards better compatibility with new generations of processors, particularly in the context of older hardware or virtualization events, cannot be done without this critical optimization. Issue Consequences

Fix made in Linux 6.15-rc4 Inadequate memory management > 4 GB on 32-bit systems Kernel crashes, instabilities, data loss
Removing non-addressable memory blocks in HIGHMEM code Memory media limitation Gradual obsolescence of old systems
Adaptation to the new 4 GB ceiling, fixes for atypical configurations Build errors in limited environments Incompatibilities during specific compilations
Fixes to stabilize compilation in various contexts Technical solutions in the Linux 6.15-rc4 update for 32-bit architectures Technical solutions in the Linux 6.15-rc4 update for 32-bit architectures

Linux kernel developers have focused their efforts on thoroughly overhauling the memory manager, including changing the way memory is allocated and deployed on 32-bit architectures. First of all, this version introduces new logic in the management of HIGHMEM, now preventing unusable memory areas from causing a crash. The method relies on the pure and simple deletion of memory blocks that exceed the addressing capacity of these systems, thus reducing the overhead of the memory manager. This stabilization is not just a technical improvement; Above all, it guarantees more lasting compatibility with evolving hardware configurations.

Redesign of the HIGHMEM code

: cleaning and removing unwanted blocks.

  1. Better physical memory management : intelligent allocation and overflow error prevention.
  2. Compilation optimization : bug fixes on various build environments.
  3. Enhanced stability testing : validation on multiple configurations, including virtualized systems.
  4. Increased compatibility : compatibility with existing hardware, including older or limited hardware.
  5. Impacts and outlook for the Linux ecosystem, Ubuntu, and other major distributions This patch, although seemingly minor from a technical perspective, has a profound impact on the stability of many distributions, particularly for users of

Ubuntu

, Fedora, and Arch Linux . The need to ensure backward compatibility with these older architectures has become a strategic issue. Tests have shown that in some cases, the main elements impacted by the update relate to stability during memory scaling, thus strengthening the robustness of older systems. https://www.youtube.com/watch?v=_G_weGmmwjM The Challenges for Open Source OS Developers and Vendors Facing 32-Bit LimitsThe Challenges for Open Source OS Developers and Vendors Facing 32-Bit Limits

Maintaining compatibility with architectures limited to 4 GB of RAM in a world increasingly focused on virtualization and high-speed computing is a continuing challenge. The Linux 6.15-rc4 update demonstrates that these challenges are driving a complete rethinking of memory management. For distributions such as Red Hat, OpenSUSE, or Gentoo, it is becoming essential to integrate these fixes quickly to ensure optimal compatibility and avoid additional costs related to last-minute patches or problematic deployments.

Distribution

Main Impact

Recommended Actions UbuntuImproved stability on older hardware with memory > 4 GB Rapid update to Linux 6.15-rc4 via PPA or custom buildFedora Increased support for legacy architecturesExtensive testing before deployment in IT systems

Arch Linux Strengthened compatibility for activating new modules Immediate integration thanks to nightly packages
Red Hat Reliability in its production environments Strict validation and controlled deployment
OpenSUSE and Gentoo Long-term stability Kernel adaptation and business optimization