Re: [PATCH 1/3] net: mdio: unexport __init-annotated mdio_bus_init()

[Florian Fainelli]

On 6/6/2022 6:53 AM, Masahiro Yamada wrote:
> EXPORT_SYMBOL and __init is a bad combination because the .init.text
> section is freed up after the initialization. Hence, modules cannot
> use symbols annotated __init. The access to a freed symbol may end up
> with kernel panic.
>
> modpost used to detect it, but it has been broken for a decade.
>
> Recently, I fixed modpost so it started to warn it again, then this
> showed up in linux-next builds.
>
> There are two ways to fix it:
>
>    - Remove __init
>    - Remove EXPORT_SYMBOL
>
> I chose the latter for this case because the only in-tree call-site,
> drivers/net/phy/phy_device.c is never compiled as modular.
> (CONFIG_PHYLIB is boolean)
>
> Fixes: 90eff9096c01 ("net: phy: Allow splitting MDIO bus/device support from PHYs")
> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>

Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
--
Florian