From e67423c7b4f20c327de533b068907aab33720482 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 15 Oct 2014 10:22:33 +1030 Subject: [PATCH] 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 Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell --- drivers/scsi/virtio_scsi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) 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) -- 2.20.1