From: Masahiro Yamada <masahiroy@kernel.org>
Date: Mon, 6 Jun 2022 04:53:53 +0000 (+0900)
Subject: net: mdio: unexport __init-annotated mdio_bus_init()
X-Git-Tag: baikal/aarch64/sdk6.1~3763^2~15^2~2
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=24e34cdaf96c2f170d51329ce65bb1587f3c5442;p=kernel.git

net: mdio: unexport __init-annotated mdio_bus_init()

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: 66627e97e10e ("net: phy: Allow splitting MDIO bus/device support from PHYs")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 58d602985877b..8a2dbe849866d 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -1046,7 +1046,6 @@ int __init mdio_bus_init(void)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(mdio_bus_init);
 
 #if IS_ENABLED(CONFIG_PHYLIB)
 void mdio_bus_exit(void)