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/gpio/gpiolib-shared.h | 51 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 drivers/gpio/gpiolib-shared.h (limited to 'drivers/gpio/gpiolib-shared.h') diff --git a/drivers/gpio/gpiolib-shared.h b/drivers/gpio/gpiolib-shared.h new file mode 100644 index 000000000..618756f6c --- /dev/null +++ b/drivers/gpio/gpiolib-shared.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __LINUX_GPIO_SHARED_H +#define __LINUX_GPIO_SHARED_H + +#include + +struct gpio_device; +struct gpio_desc; +struct device; +struct fwnode_handle; + +#if IS_ENABLED(CONFIG_GPIO_SHARED) + +int gpiochip_setup_shared(struct gpio_chip *gc); +void gpio_device_teardown_shared(struct gpio_device *gdev); +int gpio_shared_add_proxy_lookup(struct device *consumer, + struct fwnode_handle *fwnode, + const char *con_id, unsigned long lflags); + +#else + +static inline int gpiochip_setup_shared(struct gpio_chip *gc) +{ + return 0; +} + +static inline void gpio_device_teardown_shared(struct gpio_device *gdev) { } + +static inline int gpio_shared_add_proxy_lookup(struct device *consumer, + struct fwnode_handle *fwnode, + const char *con_id, + unsigned long lflags) +{ + return 0; +} + +#endif /* CONFIG_GPIO_SHARED */ + +struct gpio_shared_desc { + struct gpio_desc *desc; + unsigned long cfg; + unsigned int usecnt; + unsigned int votecnt; + int def_val; + struct mutex mutex; /* serializes all proxy operations on this descriptor */ +}; + +struct gpio_shared_desc *devm_gpiod_shared_get(struct device *dev); + +#endif /* __LINUX_GPIO_SHARED_H */ -- cgit v1.3.1