In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in __mutex_lock in kernel/locking/mutex.c. This is related to mutex_can_spin_on_owner in kernel/locking/mutex.c, __btrfs_qgroup_free_meta in fs/btrfs/qgroup.c, and btrfs_insert_delayed_items in fs/btrfs/delayed-inode.c.
4.4.0-201.2334.4.0-1121.1354.15.0-1079.83~16.04.14.15.0-1091.101~16.04.14.15.0-1080.90~16.04.14.15.0-112.113~16.04.14.10.0-14.16~16.04.14.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.3+13 more4.4.0-1087.964.15.0-1050.54~16.04.14.4.0-1145.155Exploitability
AV:LAC:LPR:NUI:RScope
S:UImpact
C:NI:NA:HCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H