On 03/14, Peter Hurley wrote: > > On 03/14/2014 03:23 PM, Oleg Nesterov wrote: >> On 03/14, Peter Hurley wrote: >>> > Yes, cgroup_release_agent() is the work function that is scheduled. > >>> which requires both namespace and tty facilities. >> >> Hmm... why? >> >> The exiting task obviously can't exec. The only way to spawn a userspace >> process is call_usermodehelper(), it should work just fine, no? > > You're correct, in the immediate sense that the user command exec'd will > not inherit open file descriptors. > > But what if it expects to be able to find the intact children of > the foreground process group, and can't because the controlling tty > has already been torn down and all the children already sent SIGHUP.
Which group/tty ? call_usermodehelper() asks the workqueue thread to kthread_create/exec. See also below... > Or what if the user command expects to find and join the user namespace > of the dying process but now it's already been freed? But it can't even know who called call_usermodehelper(). Besides, cgroup_release_agent() uses UMH_WAIT_EXEC, so the caller can continue and disappear completely before the usermode process has any chance to do something. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
