Re: [syzbot] [kvm?] [net?] [virt?] WARNING in virtio_transport_send_pkt_info

[Michael S. Tsirkin]

On Fri, Aug 15, 2025 at 11:09:24AM +0100, Will Deacon wrote:
> On Tue, Aug 12, 2025 at 06:15:46AM -0400, Michael S. Tsirkin wrote:
> > On Tue, Aug 12, 2025 at 03:03:02AM -0700, syzbot wrote:
> > > Hello,
> > > 
> > > syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> > > WARNING in virtio_transport_send_pkt_info
> > 
> > OK so the issue triggers on
> > commit 6693731487a8145a9b039bc983d77edc47693855
> > Author: Will Deacon <will@xxxxxxxxxx>
> > Date:   Thu Jul 17 10:01:16 2025 +0100
> > 
> >     vsock/virtio: Allocate nonlinear SKBs for handling large transmit buffers
> >     
> > 
> > but does not trigger on:
> > 
> > commit 8ca76151d2c8219edea82f1925a2a25907ff6a9d
> > Author: Will Deacon <will@xxxxxxxxxx>
> > Date:   Thu Jul 17 10:01:15 2025 +0100
> > 
> >     vsock/virtio: Rename virtio_vsock_skb_rx_put()
> >     
> > 
> > 
> > Will, I suspect your patch merely uncovers a latent bug
> > in zero copy handling elsewhere.
> > Want to take a look?
> 
> Sorry for the delay, I was debugging something else!
> 
> I see Hillf already tried some stuff in the other thread, but I can take
> a look as well.
> 
> Will

I will be frank I don't understand how that patch makes sense though.

-- 
MST