Re: [Nbd] Random NBD connection shutdowns...

[Paul Clements <paul.clements@...856...>]

On Sun, Mar 10, 2013 at 5:53 PM, Michal Belczyk <belczyk@...1274...> wrote:
> On Sun, Mar 03, 2013 at 03:53:02PM +0100, Michal Belczyk wrote:
>> Hi there,
>>
>> a few months ago I noticed that nbd-client (kmod code actually) randomly
>> shuts down the connection during heavy parallel xdd benchmarks in my
>> local setup.  The following change to nbd.c fixed that for me:
>>
>> @@ -303,9 +303,13 @@
>>         struct request *req, *tmp;
>>         int err;
>>
>> +wait:
>>         err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq);
>> -       if (unlikely(err))
>> +       if (unlikely(err)) {
>> +               if (err == -ERESTARTSYS)
>> +                       goto wait;
>>                 goto out;
>> +       }
>>
>> Please consider pushing it upstream.
>> Thanks!
>
> I was able to hit this bug with the stock nbd-server, it is NOT
> bnbd-specific.  If this mailing list is the wrong place to submit NBD
> driver bugs, then please point me to the proper location, although I
> believe there are kernel people signed up here as well...

Thanks, I'll reformat and send upstream...

> I remember that it was fairly easy to trigger with a single volume NBD
> connection and large queuedepth passed to xdd -- can't remember if I did
> reduce the stack size before running xdd, perhaps the memory was running
> low... yes, it was over localhost, not remote.
> Thanks!
>
> --
> Michal Belczyk Sr.
>
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