qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
* [Qemu-devel] [PATCH] virtio-blk: assert on starting/stopping
@ 2016-04-03 10:37 Michael S. Tsirkin
  2016-04-03 19:59 ` Christian Borntraeger
  0 siblings, 1 reply; 7+ messages in thread
From: Michael S. Tsirkin @ 2016-04-03 10:37 UTC (permalink / raw)
  To: qemu-devel
  Cc: Kevin Wolf, qemu-block, Christian Borntraeger, Stefan Hajnoczi,
	Cornelia Huck, Paolo Bonzini

Reentrancy cannot happen while the BQL is being held,
so we should never enter this condition.

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

This is a replacement for [PATCH 9/9] virtio: remove starting/stopping
checks Christian, could you please give it a spin with debug enabled?
Since you reported above Paolo's patch triggers segfaults, I expect this
one to trigger assertions as well, which should give us more info on
the root cause.

 hw/block/dataplane/virtio-blk.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index fd06726..04e0e0d 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -203,10 +203,12 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
     VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
     int r;
 
-    if (vblk->dataplane_started || s->starting) {
+    if (vblk->dataplane_started) {
         return;
     }
 
+    assert(!s->starting);
+
     s->starting = true;
     s->vq = virtio_get_queue(s->vdev, 0);
 
@@ -257,10 +259,12 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
 
-    if (!vblk->dataplane_started || s->stopping) {
+    if (!vblk->dataplane_started) {
         return;
     }
 
+    assert(!s->stopping);
+
     /* Better luck next time. */
     if (vblk->dataplane_disabled) {
         vblk->dataplane_disabled = false;
-- 
MST

^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-04-04  8:48 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-04-03 10:37 [Qemu-devel] [PATCH] virtio-blk: assert on starting/stopping Michael S. Tsirkin
2016-04-03 19:59 ` Christian Borntraeger
2016-04-03 21:13   ` Paolo Bonzini
2016-04-04  8:10     ` Cornelia Huck
2016-04-04  8:19       ` Paolo Bonzini
2016-04-04  8:25         ` Cornelia Huck
2016-04-04  8:47           ` Michael S. Tsirkin

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).