From 6c22dc61c76b7e7d355f1697ba0ecf26d1334ba6 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Wed, 5 Feb 2020 17:34:00 +0100
Subject: [PATCH] virtio-balloon: Fix memory leak when unloading while hinting is in progress
Git-commit: 6c22dc61c76b7e7d355f1697ba0ecf26d1334ba6
Patch-mainline: v5.6-rc1
References: git-fixes
When unloading the driver while hinting is in progress, we will not
release the free page blocks back to MM, resulting in a memory leak.
Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: Liang Li <liang.z.li@intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200205163402.42627-2-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/virtio/virtio_balloon.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 2457c54b6185..6d063eeaa08a 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -970,6 +970,10 @@ static void remove_common(struct virtio_balloon *vb)
leak_balloon(vb, vb->num_pages);
update_balloon_size(vb);
+ /* There might be free pages that are being reported: release them. */
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
+ return_free_pages_to_mm(vb, ULONG_MAX);
+
/* Now we reset the device so we can clean up the queues. */
vb->vdev->config->reset(vb->vdev);
--
2.16.4