On Mon, Dec 01, 2008 at 01:15:18PM -0800, Sukadev Bhattiprolu wrote: > Greg Kurz [gkurz@xxxxxxxxxx] wrote: > | On Thu, 2008-11-27 at 02:17 +0100, Bastian Blank wrote: > | > On Tue, Nov 25, 2008 at 07:45:28PM -0800, Sukadev Bhattiprolu wrote: > | > > Currently task_active_pid_ns is not safe to call after a > | > > task becomes a zombie and exit_task_namespaces is called, > | > > as nsproxy becomes NULL. > | > Why do you need to be able to get the pid namespace from zombie > | > processes? > After exiting namespaces, the process notifies parent. With new changes > to signals (in this patchset), the signal code may need to determine > the namespace of sender (the exiting child in this case). So the parent of a process with a new pid namespace will never get a SIGCHLD? What I read in the kernel source (kernel/signal.c:do_notify_parent, include/asm-generic/siginfo.h:CLD_EXITED) is that the exit signals (SIGCHLD) are describes as sent by the kernel. > | I agree with Eric and Sukadev that task_active_pid_ns() is unsafe. There > | isn't even a /* don't use with zombies */ in pid_namespace.h... > Hmm. Its not unsafe at present. It would become unsafe if the signals code > tries to determine the namespace of sender. Why? Even now it may be used on zombie tasks. Bastian -- Vulcans do not approve of violence. -- Spock, "Journey to Babel", stardate 3842.4 _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
