In the Linux kernel, the following vulnerability has been resolved:
ext4: regenerate buddy after block freeing failed if under fc replay
This mostly reverts commit 6bd97bf273bd ("ext4: remove redundant mbregeneratebuddy()") and reintroduces mbregeneratebuddy(). Based on code in mbfreeblocks(), fast commit replay can end up marking as free blocks that are already marked as such. This causes corruption of the buddy bitmap so we need to regenerate it in that case.