Re: [syzbot] [net?] WARNING in netdev_queue_get_dma_dev

Jakub Kicinski <[email protected]> Wed, 5 Aug 2026 16:58:17 -0700

Newsgroups	gmane.linux.network,gmane.linux.kernel
Message-ID	<[email protected]>

On Wed, 5 Aug 2026 09:51:10 +0100 Pavel Begunkov wrote:
> On 8/4/26 22:00, Jakub Kicinski wrote:
> > Hi Pavel, could you TAL?  
> 
> It complains on not holding rtnl, so the netdev should be not
> qops-enabled, and we acquire it with netdev_get_by_index_lock().
> It's going to be rejected later, but not sure whether netdev->lock
> protects its device and leasing logic well in this case.

Hm, I see.

> As a quick fix, let's fail it early in zcrx if there is no qops.

I think we can switch the lockdep check in netdev_queue_get_dma_dev()
to netdev_assert_locked(dev)?  Nothing should be calling that function
under rtnl_lock so the _compat() is a brainfart.