Kernel version：16ad71c250c1 (HEAD -> linux-5.10.y, tag: v5.10.209, origin/linux-5.10.y) Linux 5.10.209 Bug reproduced steps： 1. cd (kernel source tree root)/tools/testing/selftests/bpf 2. make test_sockmap ; make test_progs 3. ./test_sockmap # 1/ 6 sockmap::txmsg test passthrough:OK # 2/ 6 sockmap::txmsg test redirect:OK # 3/ 6 sockmap::txmsg test drop:OK # 4/ 6 sockmap::txmsg test ingress redirect:OK After "# 4/ 6 sockmap::txmsg test ingress redirect:OK" display from terminal, the main process stucks and sends nothing. 4. In other terminal run " ps fax |grep sockmap " ,below is output 13076 pts/0 S+ 0:00 | \_ ./test_sockmap 13129 pts/0 S+ 0:00 | \_ ./test_sockmap 13130 pts/0 Z+ 0:00 | \_ [test_sockmap] <defunct> 13237 pts/1 S+ 0:00 \_ grep --color=auto sockmap Obversely, because of child process 13129 sleep, so the main process is stuck. My research: I use Bisection method to find the bug patch " c842a4c4ae7f bpf: sockmap, strparser, and tls are reusing qdisc_skb_cb and colliding "(on linux-5.10.y branch), it backport from v5.16-rc1 , It must due to merge high patches incompletely, Please take a few moment for this.
