$ kldload fuse; kldload cuse; cc -O2 -Wall -o tc tc.c && ./tc   (as root)
(ssh output lost to the panic — decisive evidence is the serial console below)

--- serial console ---
Cuse v0.1.37 @ /dev/cuse
panic: assertion "fmp->refcnt > 0" failed in fuse_mount at /usr/src/sys/vfs/fuse/fuse_vfsops.c:186
cpuid = 0
Trace beginning at frame 0xfffff801182d3408
fuse_mount.part.6() at fuse_mount.part.6+0x777 0xffffffff826009c7 
fuse_mount.part.6() at fuse_mount.part.6+0x777 0xffffffff826009c7 
sys_mount() at sys_mount+0x36b 0xffffffff80700b0b 
syscall2() at syscall2+0x11e 0xffffffff80bd6a0e 
Debugger("panic")

CPU0 stopping CPUs: 0x0000003e
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>