Re: bdrv_drained_begin deadlock with io-threads

[Kevin Wolf]

Am 01.04.2020 um 20:28 hat Dietmar Maurer geschrieben:
> > That's a pretty big change, and I'm not sure how it's related to
> > completed requests hanging in the thread pool instead of reentering the
> > file-posix coroutine. But I also tested it enough that I'm confident
> > it's really the first bad commit.
> > 
> > Maybe you want to try if your problem starts at the same commit?
> 
> Stefan already found that by bisecting last week:
> 
> See: https://lists.gnu.org/archive/html/qemu-devel/2020-03/msg07629.html
> 
> But, IMHO the commit is not the reason for (my) bug - It just makes
> it easier to trigger... I can see (my) bug sometimes with 4.1.1, although
> I have no easy way to reproduce it reliable.
> 
> Also, Stefan sent some patches to the list to fix some of the problems.
> 
> https://lists.gnu.org/archive/html/qemu-devel/2020-04/msg00022.html
> 
> Does that fix your problem?

It seems to fix it, yes. Now I don't get any hangs any more. (Also, I
guess this means that this day was essentially wasted because I worked
on a problem that already has a fix... *sigh*)

Kevin