The process deadlock occurs when you use the routeadd command. Please give me some advice!

The process deadlock occurs when you use the routeadd command. Please give me some advice! -- Linux general technology-Linux programming and kernel information. The following is a detailed description. My C program executes system ("route del default; route add default gw 2.11.2.1 dev eth3"); after several processes are started, the parent process is killed, the executed shell process becomes an orphan process. As a result, the process is deadlocked and you can see it in ps-ef:
Root 1192 1 0 00:00:00 pts/1 sh-c route del default; route add default gw 2.11.2.1 dev eth3
Root 1193 1 0 00:00:00 pts/1 sh-c route del default; route add default gw 2.11.2.1 dev eth3
Root 1194 1 0 00:00:00 pts/1 sh-c route del default; route add default gw 2.11.2.1 dev eth3
Root 11127 1192 0 00:00:00 pts/1 sh-c route add default gw 2.11.2.1 dev eth3
Root 11134 1193 0 00:00:00 pts/1 sh-c route add default gw 2.11.2.1 dev eth3
Root 11141 1194 0 00:00:00 pts/1 sh-c route add default gw 2.11.2.1 dev eth3
Is there any way to prevent process deadlocks after killing the parent process? Thank you!