From d9e427f6ab8142d6868eb719e6a7851aafea56b6 Mon Sep 17 00:00:00 2001
From: Jan Stancek <jstancek@redhat.com>
Date: Fri, 1 Dec 2017 10:50:28 +0100
Subject: [PATCH] virtio_balloon: fix increment of vb->num_pfns in
fill_balloon()
commit c7cdff0e8647 ("virtio_balloon: fix deadlock on OOM")
changed code to increment vb->num_pfns before call to
set_page_pfns(), which used to happen only after.
This patch fixes boot hang for me on ppc64le KVM guests.
Fixes: c7cdff0e8647 ("virtio_balloon: fix deadlock on OOM")
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/virtio/virtio_balloon.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 7960746f75978..a1fb52cb3f0ab 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -174,13 +174,12 @@ static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
while ((page = balloon_page_pop(&pages))) {
balloon_page_enqueue(&vb->vb_dev_info, page);
- vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE;
-
set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
if (!virtio_has_feature(vb->vdev,
VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
adjust_managed_page_count(page, -1);
+ vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE;
}
num_allocated_pages = vb->num_pfns;
--
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