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_ns.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) create mode 100644 drivers/rpmsg/rpmsg_ns.c (limited to 'drivers/rpmsg/rpmsg_ns.c') diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c new file mode 100644 index 000000000..bde8c8d43 --- /dev/null +++ b/drivers/rpmsg/rpmsg_ns.c @@ -0,0 +1,124 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) STMicroelectronics 2020 - All Rights Reserved + */ +#include +#include +#include +#include +#include +#include + +#include "rpmsg_internal.h" + +/** + * rpmsg_ns_register_device() - register name service device based on rpdev + * @rpdev: prepared rpdev to be used for creating endpoints + * + * This function wraps rpmsg_register_device() preparing the rpdev for use as + * basis for the rpmsg name service device. + */ +int rpmsg_ns_register_device(struct rpmsg_device *rpdev) +{ + rpdev->src = RPMSG_NS_ADDR; + rpdev->dst = RPMSG_NS_ADDR; + + return rpmsg_register_device_override(rpdev, "rpmsg_ns"); +} +EXPORT_SYMBOL(rpmsg_ns_register_device); + +/* invoked when a name service announcement arrives */ +static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len, + void *priv, u32 src) +{ + struct rpmsg_ns_msg *msg = data; + struct rpmsg_device *newch; + struct rpmsg_channel_info chinfo; + struct device *dev = rpdev->dev.parent; + int ret; + +#if defined(CONFIG_DYNAMIC_DEBUG) + dynamic_hex_dump("NS announcement: ", DUMP_PREFIX_NONE, 16, 1, + data, len, true); +#endif + + if (len != sizeof(*msg)) { + dev_err(dev, "malformed ns msg (%d)\n", len); + return -EINVAL; + } + + /* don't trust the remote processor for null terminating the name */ + msg->name[RPMSG_NAME_SIZE - 1] = '\0'; + + strscpy_pad(chinfo.name, msg->name, sizeof(chinfo.name)); + chinfo.src = RPMSG_ADDR_ANY; + chinfo.dst = rpmsg32_to_cpu(rpdev, msg->addr); + + dev_info(dev, "%sing channel %s addr 0x%x\n", + rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY ? + "destroy" : "creat", msg->name, chinfo.dst); + + if (rpmsg32_to_cpu(rpdev, msg->flags) & RPMSG_NS_DESTROY) { + ret = rpmsg_release_channel(rpdev, &chinfo); + if (ret) + dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret); + } else { + newch = rpmsg_create_channel(rpdev, &chinfo); + if (!newch) + dev_err(dev, "rpmsg_create_channel failed\n"); + } + + return 0; +} + +static int rpmsg_ns_probe(struct rpmsg_device *rpdev) +{ + struct rpmsg_endpoint *ns_ept; + struct rpmsg_channel_info ns_chinfo = { + .src = RPMSG_NS_ADDR, + .dst = RPMSG_NS_ADDR, + .name = "name_service", + }; + + /* + * Create the NS announcement service endpoint associated to the RPMsg + * device. The endpoint will be automatically destroyed when the RPMsg + * device will be deleted. + */ + ns_ept = rpmsg_create_ept(rpdev, rpmsg_ns_cb, NULL, ns_chinfo); + if (!ns_ept) { + dev_err(&rpdev->dev, "failed to create the ns ept\n"); + return -ENOMEM; + } + rpdev->ept = ns_ept; + + return 0; +} + +static struct rpmsg_driver rpmsg_ns_driver = { + .drv.name = KBUILD_MODNAME, + .probe = rpmsg_ns_probe, +}; + +static int rpmsg_ns_init(void) +{ + int ret; + + ret = register_rpmsg_driver(&rpmsg_ns_driver); + if (ret < 0) + pr_err("%s: Failed to register rpmsg driver\n", __func__); + + return ret; +} +postcore_initcall(rpmsg_ns_init); + +static void rpmsg_ns_exit(void) +{ + unregister_rpmsg_driver(&rpmsg_ns_driver); +} +module_exit(rpmsg_ns_exit); + +MODULE_DESCRIPTION("Name service announcement rpmsg driver"); +MODULE_AUTHOR("Arnaud Pouliquen "); +MODULE_ALIAS("rpmsg:" KBUILD_MODNAME); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1