4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jan Stancek <jstan...@redhat.com> commit d9e427f6ab8142d6868eb719e6a7851aafea56b6 upstream. 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 <m...@redhat.com> Cc: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp> Cc: Michal Hocko <mho...@suse.com> Cc: Wei Wang <wei.w.w...@intel.com> Cc: sta...@vger.kernel.org Signed-off-by: Jan Stancek <jstan...@redhat.com> Signed-off-by: Michael S. Tsirkin <m...@redhat.com> Signed-off-by: Sudip Mukherjee <sudipm.mukher...@gmail.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/virtio/virtio_balloon.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -174,13 +174,12 @@ static unsigned fill_balloon(struct virt 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;