CVE-2024-36021 in Linux
Summary
by MITRE • 05/30/2024
In the Linux kernel, the following vulnerability has been resolved:
net: hns3: fix kernel crash when devlink reload during pf initialization
The devlink reload process will access the hardware resources, but the register operation is done before the hardware is initialized. So, processing the devlink reload during initialization may lead to kernel crash. This patch fixes this by taking devl_lock during initialization.
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Analysis
by VulDB Data Team • 05/07/2026
The vulnerability CVE-2024-36021 affects the Linux kernel's hns3 network driver implementation, specifically addressing a critical race condition during the device initialization process. This flaw exists within the hardware network subsystem where the devlink reload functionality attempts to access hardware resources before the underlying hardware components have been properly initialized. The issue manifests as a kernel crash when the devlink reload operation is executed concurrently with the physical function (pf) initialization process, creating a scenario where register operations are performed against uninitialized hardware registers.
The technical root cause of this vulnerability lies in the improper synchronization mechanism during the driver initialization sequence. During pf initialization, the system attempts to acquire hardware resources and configure register mappings before the devlink reload process completes its operations. This creates a timing window where the reload operation accesses memory-mapped registers that have not yet been properly mapped or configured by the initialization routines. The vulnerability is classified as a race condition and falls under CWE-362, which specifically addresses concurrent execution issues that can lead to unpredictable behavior and system instability.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise network connectivity and system stability in production environments. When the kernel crashes due to this condition, it can result in complete network outages for systems relying on hns3 network adapters, particularly affecting data center and server environments where high availability is critical. The vulnerability is particularly dangerous in virtualized environments where devlink reload operations are commonly used for configuration changes without system downtime, as it can cause cascading failures across multiple virtual machines sharing the same physical hardware.
This vulnerability affects systems running Linux kernel versions that include the hns3 driver implementation, particularly those using Huawei's networking hardware or compatible network adapters. The patch resolves the issue by implementing proper locking mechanisms through the devl_lock during the initialization phase, ensuring that devlink reload operations are serialized with initialization activities. This approach aligns with ATT&CK technique T1490, which covers data destruction and system compromise through kernel-level vulnerabilities. Organizations should prioritize patching affected systems and implementing monitoring for kernel crash events that may indicate exploitation attempts. The fix demonstrates proper defensive programming practices by preventing concurrent access to hardware resources during initialization phases, thereby maintaining system integrity and preventing unauthorized access to kernel memory regions through improper register access patterns.