* [PATCH RESEND net] vhost: fix vhost_vq_access_ok() log check
[not found] <20180409131021.5132-1-stefanha@redhat.com>
@ 2018-04-09 19:40 ` Michael S. Tsirkin
2018-04-10 1:05 ` Stefan Hajnoczi
0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2018-04-09 19:40 UTC (permalink / raw)
To: David Miller, netdev, virtualization
Cc: linux-kernel, jasowang, kvm, mst, syzkaller-bugs, Stefan Hajnoczi
From: Stefan Hajnoczi <stefanha@redhat.com>
Commit d65026c6c62e7d9616c8ceb5a53b68bcdc050525 ("vhost: validate log
when IOTLB is enabled") introduced a regression. The logic was
originally:
if (vq->iotlb)
return 1;
return A && B;
After the patch the short-circuit logic for A was inverted:
if (A || vq->iotlb)
return A;
return B;
The correct logic is:
if (!A || vq->iotlb)
return A;
return B;
Reported-by: syzbot+65a84dde0214b0387ccd@syzkaller.appspotmail.com
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/vhost/vhost.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5320039671b7..f6af4210679a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1246,7 +1246,7 @@ int vhost_vq_access_ok(struct vhost_virtqueue *vq)
{
int ret = vq_log_access_ok(vq, vq->log_base);
- if (ret || vq->iotlb)
+ if (!ret || vq->iotlb)
return ret;
return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
--
2.14.3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH RESEND net] vhost: fix vhost_vq_access_ok() log check
2018-04-09 19:40 ` [PATCH RESEND net] vhost: fix vhost_vq_access_ok() log check Michael S. Tsirkin
@ 2018-04-10 1:05 ` Stefan Hajnoczi
0 siblings, 0 replies; 2+ messages in thread
From: Stefan Hajnoczi @ 2018-04-10 1:05 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: David Miller, netdev, Linux Virtualization, kvm, syzkaller-bugs,
linux-kernel, Stefan Hajnoczi
On Tue, Apr 10, 2018 at 3:40 AM, Michael S. Tsirkin <mst@redhat.com> wrote:
> From: Stefan Hajnoczi <stefanha@redhat.com>
>
> Commit d65026c6c62e7d9616c8ceb5a53b68bcdc050525 ("vhost: validate log
> when IOTLB is enabled") introduced a regression. The logic was
> originally:
>
> if (vq->iotlb)
> return 1;
> return A && B;
>
> After the patch the short-circuit logic for A was inverted:
>
> if (A || vq->iotlb)
> return A;
> return B;
>
> The correct logic is:
>
> if (!A || vq->iotlb)
> return A;
> return B;
>
> Reported-by: syzbot+65a84dde0214b0387ccd@syzkaller.appspotmail.com
> Cc: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>
> ---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
NACK
I will send a v2 with cleaner logic as suggested by Linus.
Stefan
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-04-09 19:40 ` [PATCH RESEND net] vhost: fix vhost_vq_access_ok() log check Michael S. Tsirkin
2018-04-10 1:05 ` Stefan Hajnoczi
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