On Wed, Feb 06, 2019 at 10:56:41AM -0700, Jens Axboe wrote: > On 2/5/19 6:01 PM, Al Viro wrote: > > On Tue, Feb 05, 2019 at 05:27:29PM -0700, Jens Axboe wrote: > > > >> This should be better, passes some basic testing, too: > >> > >> http://git.kernel.dk/cgit/linux-block/commit/?h=io_uring&id=01a93aa784319a02ccfa6523371b93401c9e0073 > >> > >> Verified that we're grabbing the right refs, and don't hold any > >> ourselves. For the file registration, forbid registration of the > >> io_uring fd, as that is pointless and will introduce a loop regardless > >> of fd passing. > > > > *shrug* > > > > So pass it to AF_UNIX socket and register _that_ - does't change the > > underlying problem. > > Maybe I'm being dense here, but it's an f_op match. Should catch a > passed fd as well, correct? f_op match on _what_? > With that, how can there be a loop? io_uring_fd = .... socketpair(PF_UNIX, SOCK_STREAM, 0, sock_fds); register sock_fds[0] and sock_fds[1] to io_uring_fd send SCM_RIGHTS datagram with io_uring_fd to sock_fds[0] close sock_fds[0], sock_fds[1] and io_uring_fd And there's your unreachable loop.
