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/extcon/extcon.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 drivers/extcon/extcon.h (limited to 'drivers/extcon/extcon.h') diff --git a/drivers/extcon/extcon.h b/drivers/extcon/extcon.h new file mode 100644 index 000000000..946182687 --- /dev/null +++ b/drivers/extcon/extcon.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_EXTCON_INTERNAL_H__ +#define __LINUX_EXTCON_INTERNAL_H__ + +#include + +/** + * struct extcon_dev - An extcon device represents one external connector. + * @name: The name of this extcon device. Parent device name is + * used if NULL. + * @supported_cable: Array of supported cable names ending with EXTCON_NONE. + * If supported_cable is NULL, cable name related APIs + * are disabled. + * @mutually_exclusive: Array of mutually exclusive set of cables that cannot + * be attached simultaneously. The array should be + * ending with 0 or be NULL (no mutually exclusive cables). + * For example, if it is {0x7, 0x30, 0}, then, + * {0, 1}, {0, 1, 2}, {0, 2}, {1, 2}, or {4, 5} cannot + * be attached simulataneously. {0x7, 0} is equivalent to + * {0x3, 0x6, 0x5, 0}. If it is {0xFFFFFFFF, 0}, there + * can be no simultaneous connections. + * @dev: Device of this extcon. + * @id: Unique device ID of this extcon. + * @state: Attach/detach state of this extcon. Do not provide at + * register-time. + * @nh_all: Notifier for the state change events for all supported + * external connectors from this extcon. + * @nh: Notifier for the state change events from this extcon + * @entry: To support list of extcon devices so that users can + * search for extcon devices based on the extcon name. + * @lock: Protects device state and serialises device registration + * @max_supported: Internal value to store the number of cables. + * @extcon_dev_type: Device_type struct to provide attribute_groups + * customized for each extcon device. + * @cables: Sysfs subdirectories. Each represents one cable. + * + * In most cases, users only need to provide "User initializing data" of + * this struct when registering an extcon. In some exceptional cases, + * optional callbacks may be needed. However, the values in "internal data" + * are overwritten by register function. + */ +struct extcon_dev { + /* Optional user initializing data */ + const char *name; + const unsigned int *supported_cable; + const u32 *mutually_exclusive; + + /* Internal data. Please do not set. */ + struct device dev; + unsigned int id; + struct raw_notifier_head nh_all; + struct raw_notifier_head *nh; + struct list_head entry; + int max_supported; + spinlock_t lock; /* could be called by irq handler */ + u32 state; + + /* /sys/class/extcon/.../cable.n/... */ + struct device_type extcon_dev_type; + struct extcon_cable *cables; + + /* /sys/class/extcon/.../mutually_exclusive/... */ + struct attribute_group attr_g_muex; + struct attribute **attrs_muex; + struct device_attribute *d_attrs_muex; +}; + +#endif /* __LINUX_EXTCON_INTERNAL_H__ */ -- cgit v1.3.1