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

[Breno Leitao]

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.