From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: netdev@vger.kernel.org
Cc: "Linus Walleij" <linus.walleij@linaro.org>,
"Andrew Lunn" <andrew@lunn.ch>,
"Vivien Didelot" <vivien.didelot@gmail.com>,
"Florian Fainelli" <f.fainelli@gmail.com>,
"Vladimir Oltean" <olteanv@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Bartosz Golaszewski" <bgolaszewski@baylibre.com>,
"Wolfram Sang" <wsa@kernel.org>,
linux-i2c@vger.kernel.org, "Mark Brown" <broonie@kernel.org>,
linux-spi@vger.kernel.org, "Alvin Šipraga" <alsi@bang-olufsen.dk>,
"Lino Sanfilippo" <LinoSanfilippo@gmx.de>
Subject: [PATCH net 0/2] Fix mdiobus users with devres
Date: Tue, 21 Sep 2021 00:42:07 +0300 [thread overview]
Message-ID: <20210920214209.1733768-1-vladimir.oltean@nxp.com> (raw)
Commit ac3a68d56651 ("net: phy: don't abuse devres in
devm_mdiobus_register()") by Bartosz Golaszewski has introduced two
classes of potential bugs by making the devres callback of
devm_mdiobus_alloc stop calling mdiobus_unregister.
The exact buggy circumstances are presented in the individual commit
messages. I have searched the tree for other occurrences, but at the
moment:
- for issue (a) I have no concrete proof that other buses except SPI and
I2C suffer from it, and the only SPI or I2C device drivers that call
of_mdiobus_alloc are the DSA drivers that leave a NULL
ds->slave_mii_bus and a non-NULL ds->ops->phy_read, aka ksz9477,
ksz8795, lan9303_i2c, vsc73xx-spi.
- for issue (b), all drivers which call of_mdiobus_alloc either use
of_mdiobus_register too, or call mdiobus_unregister sometime within
the ->remove path.
Although at this point I've seen enough strangeness caused by this
"device_del during ->shutdown" that I'm just going to copy the SPI and
I2C subsystem maintainers to this patch series, to get their feedback
whether they've had reports about things like this before. I don't think
other buses behave in this way, it forces SPI and I2C devices to have to
protect themselves from a really strange set of issues.
Vladimir Oltean (2):
net: dsa: don't allocate the slave_mii_bus using devres
net: dsa: realtek: register the MDIO bus under devres
drivers/net/dsa/realtek-smi-core.c | 2 +-
net/dsa/dsa2.c | 12 +++++++++---
2 files changed, 10 insertions(+), 4 deletions(-)
--
2.25.1
next reply other threads:[~2021-09-20 21:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 21:42 Vladimir Oltean [this message]
2021-09-20 21:42 ` [PATCH net 1/2] net: dsa: don't allocate the slave_mii_bus using devres Vladimir Oltean
2021-09-21 2:16 ` Florian Fainelli
2021-09-21 10:07 ` Lino Sanfilippo
2021-09-21 11:58 ` Andrew Lunn
2021-09-20 21:42 ` [PATCH net 2/2] net: dsa: realtek: register the MDIO bus under devres Vladimir Oltean
2021-09-21 12:00 ` Andrew Lunn
2021-09-21 16:22 ` Linus Walleij
2021-09-21 7:32 ` [PATCH net 0/2] Fix mdiobus users with devres Bartosz Golaszewski
2021-09-21 13:00 ` patchwork-bot+netdevbpf
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