On 8/16/20 6:45 AM, Jens Axboe wrote: > On 8/15/20 9:48 AM, Pavel Begunkov wrote: >> On 15/08/2020 18:12, Jens Axboe wrote: >>> On 8/15/20 12:45 AM, Pavel Begunkov wrote: >>>> On 13/08/2020 02:32, Jens Axboe wrote: >>>>> On 8/12/20 12:28 PM, Pavel Begunkov wrote: >>>>>> On 12/08/2020 21:22, Pavel Begunkov wrote: >>>>>>> On 12/08/2020 21:20, Pavel Begunkov wrote: >>>>>>>> On 12/08/2020 21:05, Jens Axboe wrote: >>>>>>>>> On 8/12/20 11:58 AM, Josef wrote: >>>>>>>>>> Hi, >>>>>>>>>> >>>>>>>>>> I have a weird issue on kernel 5.8.0/5.8.1, SIGINT even SIGKILL >>>>>>>>>> doesn't work to kill this process(always state D or D+), literally I >>>>>>>>>> have to terminate my VM because even the kernel can't kill the process >>>>>>>>>> and no issue on 5.7.12-201, however if IOSQE_IO_LINK is not set, it >>>>>>>>>> works >>>>>>>>>> >>>>>>>>>> I've attached a file to reproduce it >>>>>>>>>> or here >>>>>>>>>> https://gist.github.com/1Jo1/15cb3c63439d0c08e3589cfa98418b2c >>>>>>>>> >>>>>>>>> Thanks, I'll take a look at this. It's stuck in uninterruptible >>>>>>>>> state, which is why you can't kill it. >>>>>>>> >>>>>>>> It looks like one of the hangs I've been talking about a few days ago, >>>>>>>> an accept is inflight but can't be found by cancel_files() because it's >>>>>>>> in a link. >>>>>>> >>>>>>> BTW, I described it a month ago, there were more details. >>>>>> >>>>>> https://lore.kernel.org/io-uring/34eb5e5a-8d37-0cae-be6c-c6ac4d85b5d4@xxxxxxxxx >>>>> >>>>> Yeah I think you're right. How about something like the below? That'll >>>>> potentially cancel more than just the one we're looking for, but seems >>>>> kind of silly to only cancel from the file table holding request and to >>>>> the end. >>>> >>>> The bug is not poll/t-out related, IIRC my test reproduces it with >>>> read(pipe)->open(). See the previously sent link. >>> >>> Right, but in this context for poll, I just mean any request that has a >>> poll handler armed. Not necessarily only a pure poll. The patch should >>> fix your case, too. >> >> Ok. I was thinking about sleeping in io_read(), etc. from io-wq context. >> That should have the same effect. > > We already cancel any blocking work for the exiting task - but we do > that _after_ trying to cancel files, so we should probably just swap > those around in io_uring_flush(). That'll remove any need to find and > cancel those explicitly in io_uring_cancel_files(). I guess there's still the case of the task just closing the fd, not necessarily exiting. So I do agree with you that the io-wq case is still unhandled. I'll take a look... -- Jens Axboe
