| Message ID | 1378296975-17661-1-git-send-email-cornelia.huck@de.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Sep 04, 2013 at 02:16:15PM +0200, Cornelia Huck wrote: > Avoid trying to setup dataplane again if dataplane setup is already in > progress. This may happen if an eventfd is triggered during setup. > > I saw this occasionally with an experimental s390 irqfd implementation: > > virtio_blk_handle_output > -> virtio_blk_data_plane_start > -> virtio_ccw_set_host_notifier > ... > -> virtio_queue_set_host_notifier_fd_handler > -> virtio_queue_host_notifier_read > -> virtio_queue_notify_vq > -> virtio_blk_handle_output > -> virtio_blk_data_plane_start > -> vring_setup > -> hostmem_init > -> memory_listener_register > -> BOOM > > As virtio-ccw tries to follow what virtio-pci does, it might be triggerable > for other platforms as well. > > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> > --- > hw/block/dataplane/virtio-blk.c | 9 +++++++++ > 1 file changed, 9 insertions(+) Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index 5a96ccd..f2d7350 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -42,6 +42,7 @@ typedef struct { struct VirtIOBlockDataPlane { bool started; + bool starting; bool stopping; QEMUBH *start_bh; QemuThread thread; @@ -451,8 +452,15 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) return; } + if (s->starting) { + return; + } + + s->starting = true; + vq = virtio_get_queue(s->vdev, 0); if (!vring_setup(&s->vring, s->vdev, 0)) { + s->starting = false; return; } @@ -482,6 +490,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) s->io_notifier = *ioq_get_notifier(&s->ioqueue); aio_set_event_notifier(s->ctx, &s->io_notifier, handle_io); + s->starting = false; s->started = true; trace_virtio_blk_data_plane_start(s);
Avoid trying to setup dataplane again if dataplane setup is already in progress. This may happen if an eventfd is triggered during setup. I saw this occasionally with an experimental s390 irqfd implementation: virtio_blk_handle_output -> virtio_blk_data_plane_start -> virtio_ccw_set_host_notifier ... -> virtio_queue_set_host_notifier_fd_handler -> virtio_queue_host_notifier_read -> virtio_queue_notify_vq -> virtio_blk_handle_output -> virtio_blk_data_plane_start -> vring_setup -> hostmem_init -> memory_listener_register -> BOOM As virtio-ccw tries to follow what virtio-pci does, it might be triggerable for other platforms as well. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> --- hw/block/dataplane/virtio-blk.c | 9 +++++++++ 1 file changed, 9 insertions(+)