Yi Chen <yiche@xxxxxxxxxx> wrote: > ip netns exec $S tcpdump -q --immediate-mode -Ui s_r -w ${PCAP} 2> /dev/null & > pid=$! > +sleep 0.5 You might want to add a wait_for_tcpdump_listen helper, that checks /proc/net/packet for tcpdump appearance, or /porc/$pid/fd/ for appearance of the packet socket. No need to resend and no need to work on this, just something to keep in mind of the future. I've applied all 4 patches and pushed them out, thanks for addressing all review comments.