pipe(&(0x7f00000003c0)={<r0=>0xffffffffffffffff, <r1=>0xffffffffffffffff})
write$P9_RFLUSH(r1, &(0x7f0000000000)={0x7}, 0x7)
ioctl$FIONREAD(r0, 0x541b, &(0x7f0000000100))