r0 = openat$procfs(0xffffffffffffff9c, &(0x7f0000000140)='/proc/keys\x00', 0x0, 0x0)
r1 = syz_open_dev$tty20(0xc, 0x4, 0x0)
sendfile(r1, r0, 0x0, 0x3fffffffffffc)