Re: [PATCH v2 0/3] Fix some AIO context locking in jobs

[Dietmar Maurer]

Wait - maybe this was a bug in my test setup - I am unable to reproduce now..

@Stefan Reiter: Are you able to trigger this?

> > I *think* the second patch also fixes the hangs on backup abort that I and
> > Dietmar noticed in v1, but I'm not sure, they we're somewhat intermittent
> > before too.
> 
> No, I still get this freeze:
> 
> 0  0x00007f0aa4866916 in __GI_ppoll (fds=0x7f0a12935c40, nfds=2, 
> timeout=<optimized out>, timeout@entry=0x0, sigmask=sigmask@entry=0x0)
>     at ../sysdeps/unix/sysv/linux/ppoll.c:39
> #1  0x000055d3a6c91d29 in ppoll (__ss=0x0, __timeout=0x0, __nfds=<optimized 
> out>, __fds=<optimized out>)
>     at /usr/include/x86_64-linux-gnu/bits/poll2.h:77
> #2  0x000055d3a6c91d29 in qemu_poll_ns (fds=<optimized out>, nfds=<optimized 
> out>, timeout=timeout@entry=-1) at util/qemu-timer.c:335
> #3  0x000055d3a6c94511 in fdmon_poll_wait (ctx=0x7f0a97505e80, 
> ready_list=0x7fff67e5c358, timeout=-1) at util/fdmon-poll.c:79
> #4  0x000055d3a6c93af7 in aio_poll (ctx=0x7f0a97505e80, 
> blocking=blocking@entry=true) at util/aio-posix.c:589
> #5  0x000055d3a6bf4cd3 in bdrv_do_drained_begin
>     (poll=<optimized out>, ignore_bds_parents=false, parent=0x0, 
> recursive=false, bs=0x7f0a9754c280) at block/io.c:429
> #6  0x000055d3a6bf4cd3 in bdrv_do_drained_begin
>     (bs=0x7f0a9754c280, recursive=<optimized out>, parent=0x0, 
> ignore_bds_parents=<optimized out>, poll=<optimized out>) at block/io.c:395
> #7  0x000055d3a6be5c87 in blk_drain (blk=0x7f0a97abcc00) at 
> block/block-backend.c:1617
> #8  0x000055d3a6be686d in blk_unref (blk=0x7f0a97abcc00) at 
> block/block-backend.c:473
> #9  0x000055d3a6b9e835 in block_job_free (job=0x7f0a15f44e00) at blockjob.c:89
> #10 0x000055d3a6b9fe29 in job_unref (job=0x7f0a15f44e00) at job.c:376
> #11 0x000055d3a6b9fe29 in job_unref (job=0x7f0a15f44e00) at job.c:368
> #12 0x000055d3a6ba07aa in job_finish_sync (job=job@entry=0x7f0a15f44e00, 
> finish=finish@entry=
>     0x55d3a6ba0cd0 <job_cancel_err>, errp=errp@entry=0x0) at job.c:1004
> #13 0x000055d3a6ba0cee in job_cancel_sync (job=job@entry=0x7f0a15f44e00) at 
> job.c:947