| Message ID | 20230606152501.328789-1-maxime.chevallier@bootlin.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Followup fixes for the dwmac and altera lynx conversion | expand |
On Tue, Jun 06, 2023 at 05:24:56PM +0200, Maxime Chevallier wrote: > Hello everyone, > > Here's another version of the cleanup series for the TSE PCS replacement > by PCS Lynx. It includes Kconfig fixups, some missing initialisations > and a slight rework suggested by Russell for the dwmac cleanup sequence. Thanks, this is getting there, but now you've now made me read altera_tse.c, and it suffers the same issue that dwmac-socfpga.c does: ret = register_netdev(ndev); ... priv->pcs = lynx_pcs_create_mdiodev(pcs_bus, 0); ... priv->phylink = phylink_create(&priv->phylink_config, This means you're publishing before you've finished setup - which is a racy thing to do, especially if the driver is a module. Let's think about what could happen. register_netdev() adds the network device to the net layer and publishes it to userspace. Userspace notices a new network interface and configures it, causing tse_open() to be called. However, priv->phylink has not yet been initialised. tse_open() then does: ret = phylink_of_phy_connect(priv->phylink, priv->device->of_node, 0); and phylink_of_phy_connect() attempts to dereference it's first argument, resulting in a NULL pointer dereference. Even if that doesn't get you, then: phylink_start(priv->phylink); will. Golden rule: setup everything you need first, and only once that's complete, publish. If you publish before you've completed setup, then you're giving permission for other stuff to immediately start making use of what you've published, which may occur before the remainder of the initialisation has completed. Lastly, remember that phylink_start() can result in the link coming up _immediately_ (that means mac_link_up() could be called before it's returned), so I would hope that the Altera TSE driver is prepared for that to happen before napi, queues, and rx dma are ready. Not saying that there's anything wrong with this series (there isn't), merely that there's more issues that ought to be resolved. Thanks.
Hello everyone, Here's another version of the cleanup series for the TSE PCS replacement by PCS Lynx. It includes Kconfig fixups, some missing initialisations and a slight rework suggested by Russell for the dwmac cleanup sequence. V2->V3 : - Fix uninitialized .autoscan field for mdio regmap configuration in both altera_tse and dwmac_socfpga V1->V2 : - Fix a Kconfig inconsistency - rework the dwmac_socfpga cleanup sequence Maxime Chevallier (5): net: altera-tse: Initialize the regmap_config struct before using it net: altera_tse: Use the correct Kconfig option for the PCS_LYNX dependency net: stmmac: make the pcs_lynx cleanup sequence specific to dwmac_socfpga net: altera_tse: explicitly disable autoscan on the regmap-mdio bus net: dwmac_socfpga: explicitly disable autoscan on the regmap-mdio bus drivers/net/ethernet/altera/Kconfig | 2 +- drivers/net/ethernet/altera/altera_tse_main.c | 2 ++ drivers/net/ethernet/stmicro/stmmac/common.h | 1 - .../net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 15 ++++++++++++++- drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 3 --- 5 files changed, 17 insertions(+), 6 deletions(-)