> Not sure this is an actual bug, but depends on how you look at it. Your > poll command has a reference to the file, which means that when you close > it here: > > assert(close(sock_listen_fd1) == 0); > > then that's not the final close. If you move the io_uring_queue_exit() > before that last create_server_socket() it should work, since the poll > will have been canceled (and hence the file closed) at that point. > > That said, I don't believe we actually need the file after arming the > poll, so we could potentially close it once we've armed it. That would > make your example work. ah okay that makes sense > Actually we do need the file, in case we're re-arming poll. But as stated > in the above email, this isn't unexpected behavior. You could cancel the > poll before trying to setup the new server socket, that'd close it as > well. Then the close() would actually close it. Ordering of the two > operations wouldn't matter. > > Just to wrap this one up, the below patch would make it behave like you > expect, and still retain the re-poll behavior we use on poll armed on > behalf of an IO request. At this point we're not holding a reference to > the file across the poll handler, and your close() would actually close > the file since it's putting the last reference to it. > > But... Not actually sure this is warranted. Any io_uring request that > operates on a file will hold a reference to it until it completes. The > poll request in your example never completes. If you run poll(2) on a > file and you close that file, you won't get a poll event triggered. > It'll just sit there and wait on events that won't come in. poll(2) > doesn't hold a reference to the file once it's armed the handler, so > your example would work there. oh thanks I'm gonna test that :) yeah I expected exactly the same behaviour as in epoll(2) & pol(2) that's why I'm asking to be honest it would be quite handy to have this patch(for netty), so I don't have to cancel a poll or close ring file descriptor(I do of course understand that if you won't push this patch) is there no other way around to close the file descriptor? Even if I remove the poll, it doesn't work btw if understood correctly poll remove operation refers to all file descriptors which arming a poll in the ring buffer right? Is there a way to cancel a specific file descriptor poll? --- Josef Grieb
