[PATCH 3.11 139/233] virtio-scsi: Fix hotcpu_notifier use-after-free with virtscsi_freeze

From: Luis Henriques
Date: Fri Feb 07 2014 - 07:30:29 EST


3.11.10.4 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Asias He <asias.hejun@xxxxxxxxx>

commit f466f75385369a181409e46da272db3de6f5c5cb upstream.

vqs are freed in virtscsi_freeze but the hotcpu_notifier is not
unregistered. We will have a use-after-free usage when the notifier
callback is called after virtscsi_freeze.

Fixes: 285e71ea6f3583a85e27cb2b9a7d8c35d4c0d558
("virtio-scsi: reset virtqueue affinity when doing cpu hotplug")

Signed-off-by: Asias He <asias.hejun@xxxxxxxxx>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/scsi/virtio_scsi.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 74b88ef..b26f1a5 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -957,6 +957,10 @@ static void virtscsi_remove(struct virtio_device *vdev)
#ifdef CONFIG_PM
static int virtscsi_freeze(struct virtio_device *vdev)
{
+ struct Scsi_Host *sh = virtio_scsi_host(vdev);
+ struct virtio_scsi *vscsi = shost_priv(sh);
+
+ unregister_hotcpu_notifier(&vscsi->nb);
virtscsi_remove_vqs(vdev);
return 0;
}
@@ -965,8 +969,17 @@ static int virtscsi_restore(struct virtio_device *vdev)
{
struct Scsi_Host *sh = virtio_scsi_host(vdev);
struct virtio_scsi *vscsi = shost_priv(sh);
+ int err;
+
+ err = virtscsi_init(vdev, vscsi);
+ if (err)
+ return err;
+
+ err = register_hotcpu_notifier(&vscsi->nb);
+ if (err)
+ vdev->config->del_vqs(vdev);

- return virtscsi_init(vdev, vscsi);
+ return err;
}
#endif

--
1.8.3.2

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