virtio: handle > 2 billion page balloon targets
If the host asks for a huge target towards_target() can overflow, and
we up oops as we try to release more pages than we have. The simple
fix is to use a 64-bit value.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index c8a4332..0b3efc3 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -152,7 +152,7 @@
wake_up(&vb->config_change);
}
-static inline int towards_target(struct virtio_balloon *vb)
+static inline s64 towards_target(struct virtio_balloon *vb)
{
u32 v;
__virtio_config_val(vb->vdev,
@@ -176,7 +176,7 @@
set_freezable();
while (!kthread_should_stop()) {
- int diff;
+ s64 diff;
try_to_freeze();
wait_event_interruptible(vb->config_change,
