virtio: fix oops on OOM
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> Cc: stable@kernel.org # .34.x Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 changed files with 3 additions and 2 deletions
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@ -164,7 +164,8 @@ int virtqueue_add_buf_gfp(struct virtqueue *_vq,
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gfp_t gfp)
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gfp_t gfp)
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{
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{
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struct vring_virtqueue *vq = to_vvq(_vq);
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struct vring_virtqueue *vq = to_vvq(_vq);
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unsigned int i, avail, head, uninitialized_var(prev);
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unsigned int i, avail, uninitialized_var(prev);
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int head;
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START_USE(vq);
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START_USE(vq);
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@ -174,7 +175,7 @@ int virtqueue_add_buf_gfp(struct virtqueue *_vq,
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* buffers, then go indirect. FIXME: tune this threshold */
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* buffers, then go indirect. FIXME: tune this threshold */
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if (vq->indirect && (out + in) > 1 && vq->num_free) {
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if (vq->indirect && (out + in) > 1 && vq->num_free) {
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head = vring_add_indirect(vq, sg, out, in, gfp);
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head = vring_add_indirect(vq, sg, out, in, gfp);
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if (head != vq->vring.num)
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if (likely(head >= 0))
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goto add_head;
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goto add_head;
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}
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}
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