[RFC][PATCH] Disable CLONE_PARENT for init

Roland McGrath roland at redhat.com
Wed Jul 1 00:46:54 PDT 2009

> When global or container-init processes use CLONE_PARENT, they create a
> multi-rooted process tree. 

I take this to be the real motivation for your change.
But you don't mention it in the code comment.

> +	 * Swapper process sets the handler for SIGCHLD to SIG_DFL. If init
> +	 * creates a sibling and the sibling exits, the SIGCHLD is sent to
> +	 * the swapper (since the swapper's handler for SIGCHLD is SIG_DFL).
> +	 * But since the swapper does not reap its children, the zombie will
> +	 * remain forever. So prevent init from using CLONE_PARENT.

This would be fixed by having swapper set its SIGCHLD to SIG_IGN instead,
so such children self-reap.  That seems like the better fix for that.

If you want to make this change because of container-init issues, I think
you should just say so independent of this global-init case.


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