On Tue, Jan 28, 2020 at 8:42 PM Jens Axboe <axboe@xxxxxxxxx> wrote: > On 1/28/20 11:04 AM, Jens Axboe wrote: > > On 1/28/20 10:19 AM, Jens Axboe wrote: [...] > >> #1 adds support for registering the personality of the invoking task, > >> and #2 adds support for IORING_OP_USE_CREDS. Right now it's limited to > >> just having one link, it doesn't support a chain of them. [...] > I didn't like it becoming a bit too complicated, both in terms of > implementation and use. And the fact that we'd have to jump through > hoops to make this work for a full chain. > > So I punted and just added sqe->personality and IOSQE_PERSONALITY. > This makes it way easier to use. Same branch: > > https://git.kernel.dk/cgit/linux-block/log/?h=for-5.6/io_uring-vfs-creds > > I'd feel much better with this variant for 5.6. Some general feedback from an inspectability/debuggability perspective: At some point, it might be nice if you could add a .show_fdinfo handler to the io_uring_fops that makes it possible to get a rough overview over the state of the uring by reading /proc/$pid/fdinfo/$fd, just like e.g. eventfd (see eventfd_show_fdinfo()). It might be helpful for debugging to be able to see information about the fixed files and buffers that have been registered. Same for the personalities; that information might also be useful when someone is trying to figure out what privileges a running process actually has.
