Commit 078e0d59 authored by Andrew Lunn's avatar Andrew Lunn Committed by Jakub Kicinski
Browse files

dsa: qca8k: Use nested lock to avoid splat 



qca8k_phy_eth_command() is used to probe the child MDIO bus while the
parent MDIO is locked. This causes lockdep splat, reporting a possible
deadlock. It is not an actually deadlock, because different locks are
used. By making use of mutex_lock_nested() we can avoid this false
positive.

Signed-off-by: default avatarAndrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20241110175955.3053664-1-andrew@lunn.ch


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent b169e76e

drivers/net/dsa/qca/qca8k-8xxx.c

+1 −1
Original line number Diff line number Diff line
@@ -673,7 +673,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy, 
	 * We therefore need to lock the MDIO bus onto which the switch is

	 * connected.

	 */

	mutex_lock(&priv->bus->mdio_lock);

	mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);



	/* Actually start the request:

	 * 1. Send mdio master packet