golang exec.Command cause a lot of defunct processes

user_3296612 0
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I'm using golang to call pppd and then kill it after a while. However I got a lot of defunct proccesses in this way.

This is how I run pppd

exec.Command("sh", "-c", "pppd call vpn").CombinedOutput()

This is how I kill it.

exec.Command("sh", "-c", "pkill pppd").CombinedOutput()

Then I got a lot of this

root     31541 23536  0 10:54 ?        00:00:00 [pppd] <defunct>
root     31929 23356  0 10:55 ?        00:00:00 [pptpgw] <defunct>
root     31933 23356  0 10:55 ?        00:00:00 [pptpcm] <defunct>
root     31940 23356  0 10:55 ?        00:00:00 [pppd] <defunct>
root     31993 23536  0 10:55 ?        00:00:00 [pptpgw] <defunct>
root     31997 23536  0 10:55 ?        00:00:00 [pptpcm] <defunct>
root     31998 23536  0 10:55 ?        00:00:00 [pppd] <defunct>
root     32012 23356  0 10:55 ?        00:00:00 [pptpgw] <defunct>
root     32016 23356  0 10:55 ?        00:00:00 [pptpcm] <defunct>
root     32017 23356  0 10:56 ?        00:00:00 [pppd] <defunct>
root     32070 23536  0 10:56 ?        00:00:00 [pptpgw] <defunct>
root     32074 23536  0 10:56 ?        00:00:00 [pptpcm] <defunct>
root     32075 23536  0 10:56 ?        00:00:00 [pppd] <defunct>
root     32083 23356  0 10:56 ?        00:00:00 [pptpgw] <defunct>
root     32087 23356  0 10:56 ?        00:00:00 [pptpcm] <defunct>
root     32089 23356  0 10:56 ?        00:00:00 [pppd] <defunct>
root     32131 23536  0 10:57 ?        00:00:00 [pptpgw] <defunct>
root     32135 23536  0 10:57 ?        00:00:00 [pptpcm] <defunct>
root     32148 23536  0 10:57 ?        00:00:00 [pppd] <defunct>
root     32160 23356  0 10:57 ?        00:00:00 [pptpgw] <defunct>
root     32164 23356  0 10:57 ?        00:00:00 [pptpcm] <defunct>
root     32165 23356  0 10:57 ?        00:00:00 [pppd] <defunct>
root     32177 23536  0 10:57 ?        00:00:00 [pptpgw] <defunct>
root     32181 23536  0 10:57 ?        00:00:00 [pptpcm] <defunct>

How can I avoid defunct processes.

pptp go
3 Answers

A simpler way to cancel your command would be to use exec.CommandContext. e.g.

ctx, cancel := context.WithCancel(context.Background())
exec.CommandContext(ctx, "pppd", "call", "vpn").CombinedOutput()

// in some other goroutine...
cancel()

Maybe this would solve your zombie problem?

user_6382240

run subprocess in a new thread

go exec.Command("sh", "-c", "pppd call vpn").CombinedOutput()

kill subprocess

exec.Command("pkill", "pppd").CombinedOutput().CombinedOutput()
user_66303860
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