[PATCH] virtio-rng: Remove false BUG for spurious callbacks

From: Rusty Russell
Date: Thu Apr 23 2009 - 03:13:22 EST


From: Christian Borntraeger <borntraeger@xxxxxxxxxx>

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>
---
drivers/char/hw_random/virtio-rng.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/char/hw_random/virtio-rng.c
===================================================================
--- linux-2.6.orig/drivers/char/hw_random/virtio-rng.c
+++ linux-2.6/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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