[patch 13/58] virtio-rng: Remove false BUG for spurious callbacks

[Greg KH]

2.6.29-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Christian Borntraeger <borntraeger@xxxxxxxxxx>

upstream commit: e5b89542ea18020961882228c26db3ba87f6e608

The virtio-rng drivers checks for spurious callbacks. Since
callbacks can be implemented via shared interrupts (e.g. PCI) this
could lead to guest kernel oopses with lots of virtio devices.

Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
 drivers/char/hw_random/virtio-rng.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -37,9 +37,9 @@ static void random_recv_done(struct virt
 {
 	int len;
 
-	/* We never get spurious callbacks. */
+	/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
 	if (!vq->vq_ops->get_buf(vq, &len))
-		BUG();
+		return;
 
 	data_left = len / sizeof(random_data[0]);
 	complete(&have_data);


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