> On Mar 13, 2011 5:44 PM, "Samuel Thibault" <samuel.thiba...@gnu.org> wrote: > > - diskfs_S_dir_lookup is called, which for some reason ends up calling > > - fshelp_fetch_root(), which calls > > - reauth(), which calls > > - mach_reply_port() to get a rendez-vous port, and then issues > > - io_reauthenticate() with that port on ext2fs itself (since it's the > > root of the system), thus triggering a call to: > > - diskfs_S_io_reauthenticate() in another thread. There, the > > rendez-vous port is thus the same as the reply port obtained above, > > with the *same name*. > > - reauth() destroys the rendez-vous port (and thus the name!) > > - a bit later, diskfs_S_io_reauthenticate has finished its work, > > and deallocates its rendez-vous port. But the name doesn't exist any > > more. Bad. > > I think the second call to reauth should use a second, newly-created, > rendezvous port. Why doesn't it?
There is only one reauth here, it's ext2fs itself reauthenticating an fd to itself, to be used by fshelp_fetch_root for some setuid program execution. Thus the same name since it's the same port, which is wanted precisely since that's a rendez-vous port. Samuel
