[PATCH net] net: spacemit: Hold RTNL lock in emac_resume() and emac_suspend()

[Andrew Lunn]

On Fri, Nov 06, 2026 at 03:44:50PM +0500, Ali Tariq wrote:
> 
> 
> On 11/6/26 2:43 PM, Troy Mitchell wrote:
> > On Thu,  5 Nov 2026 17:34:37 +0500, Ali Tariq wrote:
> > > @@ -2056,7 +2059,9 @@ static int emac_suspend(struct device *dev)
> > >   		return 0;
> > >   	}
> > > +	rtnl_lock();
> > >   	emac_stop(ndev);
> > > +	rtnl_unlock();
> > >   	clk_disable_unprepare(priv->bus_clk);
> > >   	netif_device_detach(ndev);
> > This can deadlock. emac_stop() -> emac_down() calls
> > cancel_work_sync(&priv->tx_timeout_task) with RTNL now held, while
> > emac_tx_timeout_task() starts with rtnl_lock().
> > 
> 
> Thanks Troy, that makes sense.
> 
> For the deadlock, I think the correct function to call is rtnl_trylock()
> inside the emac_tx_timeout_task(), which would return if the lock is already
> held and will hold the lock if it is not.

rtnl_trylock() is generally a workaround needed for badly written
code. Please try to avoid it.

	Andrew