Linux Kernel Btrfs Deadlock Vulnerability in Zone Activation

A deadlock vulnerability has been identified in the Linux kernel's Btrfs file system, specifically within the zoned storage management. The issue arises in the 'btrfs_can_activate_zone' function, which can be called while holding the 'device_list_mutex'. This creates a scenario where the function attempts to acquire the same mutex again, leading to a deadlock. The problem occurs during the chunk allocation process, where the mutex is already held, causing a recursive locking situation. The vulnerability affects Linux kernel versions prior to 5.17.0.

Impact

Exploitation of this vulnerability leads to a deadlock condition, causing the system to hang indefinitely while waiting for a lock to be released.

Reproduction

The vulnerability can be reproduced by triggering the chunk allocation process in Btrfs while the 'device_list_mutex' is already held. This can be done by initiating a zone activation or similar operation that requires chunk allocation, which will then attempt to acquire the 'device_list_mutex' again, resulting in a deadlock.

Remediation

Users can upgrade to Linux kernel version 5.17.0 or later, where this vulnerability has been addressed.