Linux Kernel Wait Queue Initialization Vulnerability in Refscale Test

A vulnerability in the Linux kernel's handling of wait queues can lead to a kernel crash. This issue arises in the refscale performance test, where a reader thread may access an uninitialized wait queue. The problem occurs because the wait queue initialization is delayed, allowing the thread to read from a memory address that causes a page fault. This vulnerability affects the Linux kernel stable tree and has been addressed by ensuring proper initialization of the wait queue before the thread is created.

Impact

The vulnerability can cause a kernel panic by leading to a page fault error, where the kernel tries to access a non-existent memory page, disrupting normal operations and potentially causing a system crash.

Reproduction

To reproduce this vulnerability, run the refscale test in the Linux kernel stable tree. The test should be executed on a system with a Dell PowerEdge R750 server. During the test, the kernel may crash, displaying a page fault error caused by a reader thread accessing an uninitialized wait queue. This issue can be consistently reproduced by running the refscale test after the vulnerability has been introduced, but before it has been fixed.

Remediation

Users can upgrade to the latest version of the Linux kernel stable tree, where this vulnerability has been fixed. Instructions for downloading the patched version are available on the official Linux kernel website.