On 9/4/20 11:50 PM, Pavel Begunkov wrote: > On 05/09/2020 07:35, Jens Axboe wrote: >> On 9/4/20 9:57 PM, Jens Axboe wrote: >>> On 9/4/20 9:53 PM, Jens Axboe wrote: >>>> On 9/4/20 9:22 PM, nick@xxxxxxxxxxxx wrote: >>>>> Hi, >>>>> >>>>> I am helping out with the netty io_uring integration, and came across >>>>> some strange behaviour which seems like it might be a bug related to >>>>> async offload of read/write iovecs. >>>>> >>>>> Basically a WRITEV SQE seems to fail reliably with -BADADDRESS when the >>>>> IOSQE_ASYNC flag is set but works fine otherwise (everything else the >>>>> same). This is with 5.9.0-rc3. >>>> >>>> Do you see it just on 5.9-rc3, or also 5.8? Just curious... But that is >>>> very odd in any case, ASYNC writev is even part of the regular tests. >>>> Any sort of deferral, be it explicit via ASYNC or implicit through >>>> needing to retry, saves all the needed details to retry without >>>> needing any of the original context. >>>> >>>> Can you narrow down what exactly is being written - like file type, >>>> buffered/O_DIRECT, etc. What file system, what device is hosting it. >>>> The more details the better, will help me narrow down what is going on. >>> >>> Forgot, also size of the IO (both total, but also number of iovecs in >>> that particular request. >>> >>> Essentially all the details that I would need to recreate what you're >>> seeing. >> >> Turns out there was a bug in the explicit handling, new in the current >> -rc series. Can you try and add the below? > > Hah, absolutely the same patch was in a series I was going to send > today, but with a note that it works by luck so not a bug. Apparently, > it is :)> > BTW, const in iter->iov is guarding from such cases, yet another proof > that const casts are evil. Definitely, not a great idea to begin with... -- Jens Axboe
