Linux Kernel Deadlock Vulnerability in Hugetlb File Folio Migration

A deadlock vulnerability has been identified in the Linux kernel's handling of hugetlb file folios. This issue arises during the migration of huge pages, where the lock ordering is incorrect. Task 5749 holds the folio lock and then attempts to acquire the i_mmap_rwsem read lock, while Task 5754 holds the i_mmap_rwsem write lock and tries to acquire the folio lock, leading to a deadlock. The vulnerability is present in the Linux kernel stable tree.

Impact

Exploitation of this vulnerability leads to a deadlock, causing tasks to wait indefinitely for each other, which can disrupt system operations and performance.

Reproduction

The vulnerability can be reproduced by initiating a migration of hugetlb file folios while another task is holding the i_mmap_rwsem write lock. This creates a conflict where one task waits for a lock held by another, leading to a deadlock situation.

Remediation

The vulnerability has been addressed by correcting the lock ordering in the migration process. Users should update to the latest version of the Linux kernel stable tree where this fix has been applied.