CVE-2025-68321 in Linux
Summary
by MITRE • 12/16/2025
In the Linux kernel, the following vulnerability has been resolved:
page_pool: always add GFP_NOWARN for ATOMIC allocations
Driver authors often forget to add GFP_NOWARN for page allocation from the datapath. This is annoying to users as OOMs are a fact of life, and we pretty much expect network Rx to hit page allocation failures during OOM. Make page pool add GFP_NOWARN for ATOMIC allocations by default.
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Analysis
by VulDB Data Team • 02/22/2026
The vulnerability identified as CVE-2025-68321 addresses a critical issue within the Linux kernel's page pool subsystem that affects network driver functionality and system stability during resource contention scenarios. This flaw specifically impacts how atomic page allocations are handled within the kernel's memory management framework, particularly in network data paths where memory allocation failures are expected and should be managed gracefully without generating excessive user-space notifications.
The technical root cause of this vulnerability lies in the inconsistent handling of GFP (Get Free Page) flags during atomic memory allocations within the page pool mechanism. When network drivers perform page allocations from the datapath, they frequently omit the GFP_NOWARN flag, which is essential for suppressing overly verbose error messages during normal operation conditions. This oversight becomes particularly problematic during Out-of-Memory (OOM) situations where network receive operations legitimately encounter page allocation failures as part of their normal operational behavior. The absence of proper flag handling results in excessive logging and user-space noise that can obscure genuine system issues while potentially overwhelming system resources with repeated error reporting.
The operational impact of this vulnerability manifests primarily as increased system noise and potential performance degradation during normal network operations under memory pressure. Network drivers that fail to properly handle atomic allocations generate spurious error messages that can flood system logs and potentially impact system responsiveness. This behavior is particularly concerning in high-throughput network environments where the datapath experiences frequent page allocation attempts that may legitimately fail during memory exhaustion conditions. The vulnerability essentially forces system administrators to filter through excessive error messages while potentially missing actual system problems that require attention.
The kernel developers have implemented a resolution that automatically adds the GFP_NOWARN flag for all atomic allocations within the page pool subsystem. This change ensures that when page pool performs atomic allocations during network receive operations, the system will not generate verbose error messages for expected allocation failures. This mitigation strategy aligns with established best practices for handling memory allocation failures in high-frequency system paths where such failures are anticipated and should not trigger user-space notifications. The fix essentially makes the page pool subsystem more resilient to normal operational conditions while maintaining proper error reporting for actual system failures.
This vulnerability demonstrates the importance of proper memory management practices in kernel space, particularly when dealing with high-frequency allocation paths such as network datapaths. The solution addresses a fundamental issue in how the kernel handles expected allocation failures, ensuring that system logs remain meaningful and that administrators can focus on genuine system problems rather than routine operational conditions. The fix also reflects industry standards for kernel development practices, specifically concerning the appropriate use of GFP flags to control error message generation during memory allocation operations.
The implementation of this fix provides a more robust and user-friendly system behavior by reducing noise in system logs while maintaining proper error handling for actual failures. Network drivers no longer need to remember to add the GFP_NOWARN flag manually, as the page pool subsystem now handles this automatically for atomic allocations. This change improves system reliability and reduces administrative overhead while maintaining the integrity of the kernel's memory management subsystem. The solution represents a standard approach to handling expected allocation failures in kernel space, aligning with established practices in operating system design and memory management.