On Sat, Jan 17, 2009 at 3:26 PM, Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> wrote: > > Container-init must behave like global-init to processes within the > container and hence it must be immune to unhandled fatal signals from > within the container (i.e SIG_DFL signals that terminate the process). > > But the same container-init must behave like a normal process to > processes in ancestor namespaces and so if it receives the same fatal > signal from a process in ancestor namespace, the signal must be > processed. > > Implementing these semantics requires that send_signal() determine pid > namespace of the sender but since signals can originate from workqueues/ > interrupt-handlers, determining pid namespace of sender may not always > be possible or safe. > > This patchset implements the design/simplified semantics suggested by > Oleg Nesterov. The simplified semantics for container-init are: > > - container-init must never be terminated by a signal from a > descendant process. > > - container-init must never be immune to SIGKILL from an ancestor > namespace (so a process in parent namespace must always be able > to terminate a descendant container). > > - container-init may be immune to unhandled fatal signals (like > SIGUSR1) even if they are from ancestor namespace (SIGKILL is > the only reliable signal from ancestor namespace). SIGSTOP is normally uncatchable; I note that patch 4 states that SIGSTOP is allowed through to container-init, but given this summary is SIGSTOP still reliable when sent to a container-init from an ancestor namespace? _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
