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/rpmsg/rpmsg_char.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 drivers/rpmsg/rpmsg_char.h (limited to 'drivers/rpmsg/rpmsg_char.h') diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h new file mode 100644 index 000000000..117d9cbc5 --- /dev/null +++ b/drivers/rpmsg/rpmsg_char.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2022, STMicroelectronics + */ + +#ifndef __RPMSG_CHRDEV_H__ +#define __RPMSG_CHRDEV_H__ + +#if IS_ENABLED(CONFIG_RPMSG_CHAR) +/** + * rpmsg_chrdev_eptdev_create() - register char device based on an endpoint + * @rpdev: prepared rpdev to be used for creating endpoints + * @parent: parent device + * @chinfo: associated endpoint channel information. + * + * This function create a new rpmsg char endpoint device to instantiate a new + * endpoint based on chinfo information. + */ +int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, + struct rpmsg_channel_info chinfo); + +/** + * rpmsg_chrdev_eptdev_destroy() - destroy created char device endpoint. + * @data: private data associated to the endpoint device + * + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL + * control. + */ +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data); + +#else /*IS_ENABLED(CONFIG_RPMSG_CHAR) */ + +static inline int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent, + struct rpmsg_channel_info chinfo) +{ + return -ENXIO; +} + +static inline int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) +{ + return -ENXIO; +} + +#endif /*IS_ENABLED(CONFIG_RPMSG_CHAR) */ + +#endif /*__RPMSG_CHRDEV_H__ */ -- cgit v1.3.1