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authorMichael S. Tsirkin <mst@redhat.com>2014-10-15 10:22:33 +1030
committerRusty Russell <rusty@rustcorp.com.au>2014-10-15 10:25:12 +1030
commite67423c7b4f20c327de533b068907aab33720482 (patch)
tree48c0db846c0d9ca6bea32f87adfbfebb5b385c2c /drivers/scsi
parent1fa5b2a784dc52d929432bcc963a0bfb3a74608f (diff)
virtio_scsi: fix race on device removal
We cancel event work on device removal, but an interrupt could trigger immediately after this, and queue it again. To fix, set a flag. Loosely based on patch by Paolo Bonzini Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/virtio_scsi.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 29fd44a5d4dd..0227d39f45f0 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -110,6 +110,9 @@ struct virtio_scsi {
/* CPU hotplug notifier */
struct notifier_block nb;
+ /* Protected by event_vq lock */
+ bool stop_events;
+
struct virtio_scsi_vq ctrl_vq;
struct virtio_scsi_vq event_vq;
struct virtio_scsi_vq req_vqs[];
@@ -303,6 +306,11 @@ static void virtscsi_cancel_event_work(struct virtio_scsi *vscsi)
{
int i;
+ /* Stop scheduling work before calling cancel_work_sync. */
+ spin_lock_irq(&vscsi->event_vq.vq_lock);
+ vscsi->stop_events = true;
+ spin_unlock_irq(&vscsi->event_vq.vq_lock);
+
for (i = 0; i < VIRTIO_SCSI_EVENT_LEN; i++)
cancel_work_sync(&vscsi->event_list[i].work);
}
@@ -390,7 +398,8 @@ static void virtscsi_complete_event(struct virtio_scsi *vscsi, void *buf)
{
struct virtio_scsi_event_node *event_node = buf;
- queue_work(system_freezable_wq, &event_node->work);
+ if (!vscsi->stop_events)
+ queue_work(system_freezable_wq, &event_node->work);
}
static void virtscsi_event_done(struct virtqueue *vq)