From c558ea6dff2c2efe3329d95bbadd9cdad272dc6d Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Mon, 26 Jul 2010 16:55:30 +0930 Subject: [PATCH] virtio: fix oops on OOM commit 1fe9b6fef11771461e69ecd1bc8935a1c7c90cb5 upstream. virtio ring was changed to return an error code on OOM, but one caller was missed and still checks for vq->vring.num. The fix is just to check for <0 error code. Long term it might make sense to change goto add_head to just return an error on oom instead, but let's apply a minimal fix for 2.6.35. Reported-by: Chris Mason Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Tested-by: Chris Mason Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_ring.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 6007eba04013..dd4370b45763 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -162,7 +162,8 @@ static int vring_add_buf(struct virtqueue *_vq, void *data) { struct vring_virtqueue *vq = to_vvq(_vq); - unsigned int i, avail, head, uninitialized_var(prev); + unsigned int i, avail, uninitialized_var(prev); + int head; START_USE(vq); @@ -172,7 +173,7 @@ static int vring_add_buf(struct virtqueue *_vq, * buffers, then go indirect. FIXME: tune this threshold */ if (vq->indirect && (out + in) > 1 && vq->num_free) { head = vring_add_indirect(vq, sg, out, in); - if (head != vq->vring.num) + if (likely(head >= 0)) goto add_head; } -- 2.39.5