From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/net/mdio/mdio-regmap.c | 93 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 drivers/net/mdio/mdio-regmap.c (limited to 'drivers/net/mdio/mdio-regmap.c') diff --git a/drivers/net/mdio/mdio-regmap.c b/drivers/net/mdio/mdio-regmap.c new file mode 100644 index 000000000..8a742a8d6 --- /dev/null +++ b/drivers/net/mdio/mdio-regmap.c @@ -0,0 +1,93 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Driver for MMIO-Mapped MDIO devices. Some IPs expose internal PHYs or PCS + * within the MMIO-mapped area + * + * Copyright (C) 2023 Maxime Chevallier + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define DRV_NAME "mdio-regmap" + +struct mdio_regmap_priv { + struct regmap *regmap; + u8 valid_addr; +}; + +static int mdio_regmap_read_c22(struct mii_bus *bus, int addr, int regnum) +{ + struct mdio_regmap_priv *ctx = bus->priv; + unsigned int val; + int ret; + + if (ctx->valid_addr != addr) + return -ENODEV; + + ret = regmap_read(ctx->regmap, regnum, &val); + if (ret < 0) + return ret; + + return val; +} + +static int mdio_regmap_write_c22(struct mii_bus *bus, int addr, int regnum, + u16 val) +{ + struct mdio_regmap_priv *ctx = bus->priv; + + if (ctx->valid_addr != addr) + return -ENODEV; + + return regmap_write(ctx->regmap, regnum, val); +} + +struct mii_bus *devm_mdio_regmap_register(struct device *dev, + const struct mdio_regmap_config *config) +{ + struct mdio_regmap_priv *mr; + struct mii_bus *mii; + int rc; + + if (!config->parent) + return ERR_PTR(-EINVAL); + + mii = devm_mdiobus_alloc_size(config->parent, sizeof(*mr)); + if (!mii) + return ERR_PTR(-ENOMEM); + + mr = mii->priv; + mr->regmap = config->regmap; + mr->valid_addr = config->valid_addr; + + mii->name = DRV_NAME; + strscpy(mii->id, config->name, MII_BUS_ID_SIZE); + mii->parent = config->parent; + mii->read = mdio_regmap_read_c22; + mii->write = mdio_regmap_write_c22; + + if (config->autoscan) + mii->phy_mask = ~BIT(config->valid_addr); + else + mii->phy_mask = ~0; + + rc = devm_mdiobus_register(dev, mii); + if (rc) { + dev_err(config->parent, "Cannot register MDIO bus![%s] (%d)\n", mii->id, rc); + return ERR_PTR(rc); + } + + return mii; +} +EXPORT_SYMBOL_GPL(devm_mdio_regmap_register); + +MODULE_DESCRIPTION("MDIO API over regmap"); +MODULE_AUTHOR("Maxime Chevallier "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1