r0 = openat$tcp_mem(0xffffffffffffff9c, &(0x7f0000000000)='/proc/sys/net/ipv4/tcp_rmem\x00', 0x1, 0x0)
pwritev2(r0, &(0x7f0000000600)=[{&(0x7f0000000100)="a0", 0x1}], 0x1, 0x0, 0x0, 0x0)