CVE-2024-38391 in Linux
Summary
by MITRE • 06/21/2024
In the Linux kernel, the following vulnerability has been resolved:
cxl/region: Fix cxlr_pmem leaks
Before this error path, cxlr_pmem pointed to a kzalloc() memory, free it to avoid this memory leaking.
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Analysis
by VulDB Data Team • 05/21/2026
The vulnerability identified in the Linux kernel represents a memory leak condition within the CXL (Compute Express Link) region subsystem, specifically affecting the cxlr_pmem functionality. This issue occurs during error handling paths where allocated memory is not properly released, leading to gradual memory consumption that can impact system stability and performance over time. The problem manifests when the cxlr_pmem variable points to memory allocated through kzalloc() function but fails to execute proper deallocation before exiting the error path, creating a classic memory leak scenario.
The technical flaw stems from inadequate resource management within the kernel's CXL subsystem where memory allocated using kzalloc() is not freed during error conditions. This type of memory leak represents a violation of proper memory lifecycle management principles and can be classified under CWE-401 as "Improper Release of Memory Before Removing Last Reference." The vulnerability specifically affects the cxl/region component of the Linux kernel, which handles memory regions for CXL devices that enable high-speed communication between processors and accelerators. When error conditions occur during region management operations, the allocated memory remains unreleased, causing progressive memory consumption that can eventually lead to system resource exhaustion.
The operational impact of this vulnerability extends beyond simple memory consumption issues as it can degrade system performance and potentially cause system instability. In environments with frequent CXL region operations or high memory pressure, the cumulative effect of these leaks can result in increased memory fragmentation and reduced available system resources. The vulnerability affects systems utilizing CXL devices such as those employing CXL memory expansion or CXL cache coherency features, making it particularly relevant for high-performance computing environments, data centers, and servers that leverage these advanced memory technologies. Attackers could potentially exploit this memory leak to cause denial of service conditions by exhausting system memory resources through repeated triggering of the error path.
The recommended mitigation strategy involves implementing proper memory cleanup within error handling paths by ensuring that any memory allocated through kzalloc() is freed before exiting the function, particularly when error conditions occur. This fix aligns with the principle of defensive programming and proper resource management as outlined in various kernel security guidelines. The solution requires modifications to the cxl/region subsystem to guarantee that all allocated memory is properly released regardless of execution path taken. System administrators should apply the kernel patch that addresses this specific memory leak issue, which typically involves adding explicit free() calls for cxlr_pmem memory before returning from error conditions. The fix also emphasizes the importance of thorough testing of error paths in kernel subsystems and adherence to memory management best practices that prevent resource leaks during abnormal program execution flows.