Messages in this thread | | | Date | Wed, 1 Aug 2018 16:19:15 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v2] prctl: add PR_[GS]ET_KILLABLE |
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On 07/31, Jürg Billeter wrote: > > > Could you explain your use-case? Why a shell wants to use > > CLONE_NEWPID? > > To guarantee that there won't be any runaway processes, i.e., ensure > that no descendants (background helper daemons or misbehaving > processes) survive when the child process is terminated.
We already have PR_SET_CHILD_SUBREAPER.
Perhaps we can finally add PR_KILL_MY_DESCENDANTS_ON_EXIT? This was already discussed some time ago, but I can't find the previous discussion... Simple to implement.
> And to prevent > children from killing their ancestors.
OK, this is the only reason for CLONE_NEWPID which I can understand so far. Not that I understand why this is that useful ;)
> > > * As SIGSTOP is ignored when raised from the SIGNAL_UNKILLABLE process > > > itself, it's not possible to implement the stop action in a custom > > > SIGTSTP handler. > > > > Yes. So may be we actually want to change __isig() paths to use > > SEND_SIG_FORCED (this is not that simple), or perhaps we can change > > __send_signal() to not drop SIGSTOP sent to itself, or may be we can even > > introduce SIG_DFL_EVEN_IF_INIT, I dunno. > > In my opinion, my patch is much simpler and also more general as it
Yes, yes, let me repeat that I am not arguing with your patch, I am just trying to understand what
> > I can't understand this. An application should be changed anyway to do > > PR_SET_KILLABLE? > > PR_SET_KILLABLE can be called (e.g., by the shell) between clone() and > execve().
OK, this is true.
Oleg.
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