In the Linux kernel 5.3.11, mounting a crafted btrfs image twice can cause an rwsem_down_write_slowpath use-after-free because (in rwsem_can_spin_on_owner in kernel/locking/rwsem.c) rwsem_owner_flags returns an already freed pointer,
Exploitability
AV:LAC:LPR:HUI:NScope
S:UImpact
C:NI:NA:H4.4/CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H