Linux Kernel VMA Split Vulnerability in Tracing Buffers

A vulnerability in the Linux kernel's handling of virtual memory areas (VMAs) for trace buffer mappings has been addressed. When a VMA is split, the kernel calls the close operation on each portion. This can lead to the ring_buffer_unmap function being called multiple times, while ring_buffer_map is only called once. As a result, subsequent calls to ring_buffer_unmap return an error, triggering a warning. Trace buffer mappings require the complete buffer, including the meta page, and cannot support partial mappings. The vulnerability has been fixed by adding a callback to prevent VMA splits.

Impact

The vulnerability could cause warnings to be triggered due to improper handling of split VMAs, potentially leading to confusion or misinterpretation of the system's state.

Remediation

Users can upgrade to the latest version of the Linux kernel where this vulnerability has been addressed.