Linux Kernel Removes Unsafe Legacy Memory Functions
The removal of these functions mandates a transition to secure helper interfaces across the kernel codebase.
Updated on Oct. 21, 2026 in Cybersecurity
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Linus Torvalds has officially removed the __get_user and __put_user functions from generic Linux kernel code. These functions, which lacked essential pointer validation checks, were stripped to enhance security across the kernel architecture.
Why it matters
Removing these functions mitigates historical security vulnerabilities stemming from missing user address range checks. This transition forces developers to adopt modern, safer helper interfaces for memory access.
The kernel update, integrated into the Linux 7.4 codebase, finalizes the removal of unsafe memory access helpers. These legacy functions provided no user address range checks, exposing the system to potential pointer manipulation risks.
The players
Linus Torvalds
The primary developer and lead maintainer of the Linux kernel.
Linux kernel
The open-source monolithic kernel powering operating systems, servers, and embedded devices worldwide.
The details
The __get_user and __put_user functions were removed via a Git merge to replace them with safer alternatives. These functions traditionally lacked the pointer validation required to prevent unauthorized memory access. The process utilized Claude Code, an AI tool, to perform static analysis and execute the necessary source-to-source code transformations across the generic kernel codebase.
Timeline
2025: Implementation of scoped user access region helpers.
- 2026-10-21
Linus Torvalds merged the removal of the functions into the kernel.
The Tech Race
This development follows the 2025 implementation of scoped user access region helpers, marking a transition toward more secure memory management. The move aligns with long-term efforts to purge the codebase of legacy functions that predate modern architectural safety requirements.
Developers and system administrators using x86 and x86_64 architectures will see these legacy functions deprecated in Linux kernel 7.4. Maintenance workflows must now shift to the scoped user access helpers introduced in 2025 to ensure compatibility with future kernel releases.
The takeaway
The move signals a hardening of the kernel against memory safety vulnerabilities that have persisted for years. Developers should audit codebases for calls to the removed functions to ensure compatibility with the 7.4 kernel branch.
Further reading
For broader trends in kernel security, see the latest updates in Cybersecurity.
Source note: This article includes information reported by Phoronix.
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