On 12/8/23 16:06, Jeff Moyer wrote:
Jann Horn <jannh@xxxxxxxxxx> writes:
On Fri, Dec 8, 2023 at 4:00 PM Jeff Moyer <jmoyer@xxxxxxxxxx> wrote:
Jens Axboe <axboe@xxxxxxxxx> writes:
On Wed, 06 Dec 2023 13:26:47 +0000, Pavel Begunkov wrote:
File reference cycles have caused lots of problems for io_uring
in the past, and it still doesn't work exactly right and races with
unix_stream_read_generic(). The safest fix would be to completely
disallow sending io_uring files via sockets via SCM_RIGHT, so there
are no possible cycles invloving registered files and thus rendering
SCM accounting on the io_uring side unnecessary.
[...]
Applied, thanks!
So, this will break existing users, right?
Do you know of anyone actually sending io_uring FDs over unix domain
sockets?
I do not. However, it's tough to prove no software is doing this.
That seems to me like a fairly weird thing to do.
I am often surprised by what developers choose to do. I attribute that
to my lack of imagination.
Thinking again about who might possibly do such a thing, the only
usecase I can think of is CRIU; and from what I can tell, CRIU doesn't
yet support io_uring anyway.
I'm not lobbying against turning this off, and I'm sure Pavel had
already considered the potential impact before posting. It would be
Jens already replied, but I wanted to add that it was discussed and
decided to go forward with, because there are no too obvious / known
users, and the benefits including safety outweigh it.
good to include that information in the commit message, in my opinion.
Yeah, agree with that
--
Pavel Begunkov
