lock order reversal:
 1st 0xfffff80004700cb8 kmslk (kmslk) @ /usr/src/sys/modules/drm2/drm2/../../../dev/drm2/drm_crtc.c:1960
 2nd 0xfffff800047008a0 drmslk (drmslk) @ /usr/src/sys/modules/drm2/drm2/../../../dev/drm2/drm_gem.c:188
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0463da75e0
kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe0463da7690
witness_checkorder() at witness_checkorder+0xdad/frame 0xfffffe0463da7720
_sx_xlock() at _sx_xlock+0x75/frame 0xfffffe0463da7760
drm_gem_object_unreference_unlocked() at drm_gem_object_unreference_unlocked+0x37/frame 0xfffffe0463da7790
radeon_crtc_cursor_set() at radeon_crtc_cursor_set+0x1bc/frame 0xfffffe0463da77e0
drm_mode_cursor_ioctl() at drm_mode_cursor_ioctl+0xc5/frame 0xfffffe0463da7820
drm_ioctl() at drm_ioctl+0x381/frame 0xfffffe0463da7890
devfs_ioctl_f() at devfs_ioctl_f+0xfb/frame 0xfffffe0463da78f0
kern_ioctl() at kern_ioctl+0x22b/frame 0xfffffe0463da7950
sys_ioctl() at sys_ioctl+0x13c/frame 0xfffffe0463da79a0
amd64_syscall() at amd64_syscall+0x25a/frame 0xfffffe0463da7ab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0463da7ab0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x8024b429a, rsp = 0x7fffffffe638, rbp = 0x7fffffffe660 ---