Linux Kernel Hugetlb Memory Area Soft Lockup Vulnerability

A vulnerability in the Linux kernel's handling of hugetlb memory areas can lead to a soft lockup. This issue occurs when the mprotect() system call is applied to large hugetlb memory regions, approximately 300GB, causing the CPU to become unresponsive for an extended period. The problem has been observed in Linux kernel version 6.17-rc7.

Impact

Exploitation of this vulnerability can cause a soft lockup, where a CPU becomes unresponsive for an extended period, disrupting normal system operations.

Reproduction

The vulnerability can be reproduced by calling the mprotect() system call on a large hugetlb memory area, approximately 300GB, in a workload environment. This action will trigger a soft lockup, causing the CPU to become unresponsive for about 23 seconds.

Remediation

The vulnerability has been addressed in the Linux kernel by adding a conditional reschedule call for hugetlb memory areas during the protection change process. Users can upgrade to the latest version of the Linux kernel where this fix is applied.