On Wed, Apr 26, 2017 at 05:18:58PM +0200, Oleg Nesterov wrote: > Hi Jamie, > > On 04/25, Jamie Iles wrote: > > > > Hi Oleg, > > > > I'm back looking at SIGNAL_UNKILLABLE and debugging child reapers again, > > and the current issue is when running code in the target process, > > SIGTRAP firing and that causing SIGNAL_UNKILLABLE protection to be > > removed in force_sig_info(): > > > > if (action->sa.sa_handler == SIG_DFL) > > t->signal->flags &= ~SIGNAL_UNKILLABLE; > > Yes, this is what I meant when I said force_sig_info() needs changes too. > I was going to fix it "tomorrow" but I was distracted and then forgot. > > > @@ -1185,7 +1185,7 @@ force_sig_info(int sig, struct siginfo *info, > > struct task_struct *t) > > recalc_sigpending_and_wake(t); > > } > > } > > - if (action->sa.sa_handler == SIG_DFL) > > + if (action->sa.sa_handler == SIG_DFL && !t->ptrace) > > t->signal->flags &= ~SIGNAL_UNKILLABLE; > > ret = specific_send_sig_info(sig, info, t); > > spin_unlock_irqrestore(&t->sighand->siglock, flags); > > Not sure, let me think a bit more... and this is not enough anyway. > > perhaps we should start with this simple change, but the "real" fix > needs a lot of cleanups, although I am not sure if we will ever do this.
Okay, sounds good. I'm happy to spend more time looking at this if you have suggestions - in the context of namespaces and containers this seems more relevant than when it was just the system init that we were protecting. Jamie
