5.3.2 btrfs, ext4 and xfs: Kernel panic when freeze and unfreeze operations are performed in multiple threads

Freeze and unfreeze operations that are performed across multiple threads on any supported file system can cause the system to hang and the kernel to panic. This issue is the result of a race condition that occurs when the unfreeze operation is triggered before it is actually frozen. The resulting unlock operation attempts a write operation on a non-existent lock, which results in a kernel panic. (Bug ID 25321899)