Re: flatview_write_continue global mutex deadlock

[Paolo Bonzini]

On 03/09/20 13:16, Vladimir Sementsov-Ogievskiy wrote:
> (gdb) info thr
>   Id   Target Id                                            Frame
> * 1    Thread 0x7fb9f0f39e00 (LWP 215115) "qemu-system-x86"
> 0x00007fb9d784f54d in __lll_lock_wait () from /lib64/libpthread.so.0
> [...]
> #1  0x000056069bfbd3f1 in qemu_poll_ns (fds=0x7fb9401dcdf0, nfds=1,
> timeout=542076652475) at ../util/qemu-timer.c:347
> #2  0x000056069bfd949f in fdmon_poll_wait (ctx=0x56069e6864c0,
> ready_list=0x7fb9481fc200, timeout=542076652475) at ../util/fdmon-poll.c:79
> #3  0x000056069bfcdf4c in aio_poll (ctx=0x56069e6864c0, blocking=true)
> at ../util/aio-posix.c:601
> #4  0x000056069be80cf3 in bdrv_do_drained_begin (bs=0x56069e6c0950,
> recursive=false, parent=0x0, ignore_bds_parents=false, poll=true) at
> ../block/io.c:427
> #5  0x000056069be80ddb in bdrv_drained_begin (bs=0x56069e6c0950) at
> ../block/io.c:433
> #6  0x000056069bf1e5b4 in blk_drain (blk=0x56069e6adb50) at
> ../block/block-backend.c:1718
> #7  0x000056069ba40fb5 in ide_cancel_dma_sync (s=0x56069f0d1548) at
> ../hw/ide/core.c:723
> [...]
> #13 0x000056069bd965e2 in flatview_write_continue (fv=0x7fb9401ce100,
> addr=49152, attrs=..., ptr=0x7fb9f0f87000, len=1, addr1=0, l=1,
> mr=0x56069f0d2420) at ../exec.c:3176

So this is a vCPU thread.  The question is, why is the reconnect timer
not on the same AioContext?  If it were, aio_poll would execute it.

Paolo