| Message ID | 20241110175955.3053664-1-andrew@lunn.ch (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 078e0d596f7b5952dad8662ace8f20ed2165e2ce |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v1] dsa: qca8k: Use nested lock to avoid splat | expand |
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Sun, 10 Nov 2024 18:59:55 +0100 you wrote: > 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: Andrew Lunn <andrew@lunn.ch> > > [...] Here is the summary with links: - [net-next,v1] dsa: qca8k: Use nested lock to avoid splat https://git.kernel.org/netdev/net-next/c/078e0d596f7b You are awesome, thank you!
diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c index f8d8c70642c4..59b4a7240b58 100644 --- a/drivers/net/dsa/qca/qca8k-8xxx.c +++ b/drivers/net/dsa/qca/qca8k-8xxx.c @@ -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
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: Andrew Lunn <andrew@lunn.ch> --- drivers/net/dsa/qca/qca8k-8xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)