Re: [Qemu-devel] [PATCH] dump: Acquire BQL around vm_start() in dump thread

[Paolo Bonzini <pbonzini@redhat.com>]

On 03/05/2017 10:37, Marc-André Lureau wrote:
> Hi
> 
> On Wed, May 3, 2017 at 11:42 AM Fam Zheng <famz@redhat.com
> <mailto:famz@redhat.com>> wrote:
> 
>     On Wed, 05/03 15:28, Fam Zheng wrote:
>     > This fixes an assertion failure in the following backtrace:
> 
> Do you know if it's a regression? Is this a racy case? (I couldn't
> reproduce)

I think it's never worked since separate-thread dump was introduced.

Paolo

> 
>     >     __GI___assert_fail
>     >     memory_region_transaction_commit
>     >     memory_region_add_eventfd
>     >     virtio_pci_ioeventfd_assign
>     >     virtio_bus_set_host_notifier
>     >     virtio_blk_data_plane_start
>     >     virtio_bus_start_ioeventfd
>     >     virtio_vmstate_change
>     >     vm_state_notify
>     >     vm_prepare_start
>     >     vm_start
>     >     dump_cleanup
>     >     dump_process
>     >     dump_thread
>     >     start_thread
>     >     clone
>     >
>     > vm_start need BQL, acquire it if doing cleaning up from main thread.
> 
>     Oops, s/need/needs and s/main thread/detached thread/.
> 
>  
> With that fixed,
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com
> <mailto:marcandre.lureau@redhat.com>>
> 
> -- 
> Marc-André Lureau