[RFC][PATCH] Disable CLONE_PARENT for init
oleg at redhat.com
Wed Jul 1 01:24:52 PDT 2009
On 07/01, Roland McGrath wrote:
> > 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.
This won't fix the problem. The child won't autoreap itself if ->exit_signal
> 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.
Yes, agreed, the comment looks confusing.
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