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

[Vadim Fedorenko]

On 05/11/2026 13:40, Breno Leitao wrote:
> On Thu, Nov 05, 2026 at 05:34:37PM +0500, Ali Tariq wrote:
> > The emac_resume() calls the emac_open() and emac_suspend() calls
> > emac_stop() functions directly without holding the lock through
> > rtnl_lock(). These functions rely on phy_disconnect() which reads pointer
> > with rtnl_dereference(). But since no lock is being held,
> > rtnl_dereference throws a suspicious RCU usage on
> > Orange Pi RV2 (SpacemiT K1) warning when lockdep is enabled.
> >
> > WARNING: suspicious RCU usage
> > drivers/net/phy/phy_device.c:1831 suspicious rcu_dereference_protected() usage!
> > Call Trace:
> > phy_detach_internal+0x490/0x5f2
> > phy_disconnect+0x90/0xc0
> > emac_stop+0x114/0x626
> > emac_suspend+0xac/0x126
> > platform_pm_suspend+0x72/0xe4
> >
> > Hold RTNL lock before emac_open() and emac_stop() with rtnl_lock() and
> > release the lock when functions return with rtnl_unlock().
>
> This would work, but I am wondering if it would be possible to call rtnl
> inside the _open function, when dealing with the PHY? in other words,
> shrink the time rtnl is held.

+1, especially in emac_open() rtnl is needed only in error path case