witness: userret: returning with the following locks held:
exclusive rrwlock inode r = 0 (0xfffffd80682b9808)
#0  witness_lock+0x52e sys/kern/subr_witness.c:1163
#1  rw_enter+0x46d sys/kern/kern_rwlock.c:306
#2  rrw_enter+0x4f sys/kern/kern_rwlock.c:435
#3  VOP_LOCK+0x4b sys/kern/vfs_vops.c:602
#4  vn_lock+0x6e sys/kern/vfs_vnops.c:561
#5  sys_fchmod+0x160 sys/kern/vfs_syscalls.c:2311
#6  syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#6  syscall+0x552 sys/arch/amd64/amd64/trap.c:555
#7  Xsyscall+0x128