[patch 02/18] virtio-rng: Remove false BUG for spurious callbacks

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: virtio-rng-remove-false-bug-for-spurious-callbacks.patch --]
[-- Type: text/plain, Size: 1197 bytes --]

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

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

From: Christian Borntraeger <borntraeger@de.ibm.com>

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@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 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);