| Date | Fri, 30 Jul 2010 10:52:03 -0700 | From | Greg KH <> | Subject | [106/205] virtio: fix oops on OOM |
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2.6.34-stable review patch. If anyone has any objections, please let us know.
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From: Michael S. Tsirkin <mst@redhat.com>
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 <chris.mason@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Tested-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/virtio/virtio_ring.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -162,7 +162,8 @@ static int vring_add_buf(struct virtqueu 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 virtqueu * 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; }
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