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Commit 1fe9b6fe authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Linus Torvalds
Browse files

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: default avatarChris Mason <chris.mason@oracle.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Tested-by: default avatarChris Mason <chris.mason@oracle.com>
Cc: stable@kernel.org # .34.x
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2e65a207

drivers/virtio/virtio_ring.c

+3 −2
Original line number Diff line number Diff line
@@ -164,7 +164,8 @@ int virtqueue_add_buf_gfp(struct virtqueue *_vq, 
			  gfp_t gfp)

{

	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);
@@ -174,7 +175,7 @@ int virtqueue_add_buf_gfp(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, gfp);

		if (head != vq->vring.num)

		if (likely(head >= 0))

			goto add_head;

	}