Linux Kernel Btrfs Use-After-Free Vulnerability During Unmount Process

A use-after-free vulnerability has been identified in the Linux kernel's Btrfs file system. This issue arises during the unmount process, specifically when the cleaner kernel thread is stopped before all work queues are cleared. As a result, a worker from the delalloc_workers queue may still be active, attempting to wake up the already-destroyed cleaner thread. This leads to a use-after-free condition on the task_struct associated with the cleaner thread.

Impact

Exploitation of this vulnerability causes a use-after-free condition, which can lead to memory corruption and potentially allow for arbitrary code execution.