From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/input/serio/userio.c | 313 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 313 insertions(+) create mode 100644 drivers/input/serio/userio.c (limited to 'drivers/input/serio/userio.c') diff --git a/drivers/input/serio/userio.c b/drivers/input/serio/userio.c new file mode 100644 index 000000000..8c19975c8 --- /dev/null +++ b/drivers/input/serio/userio.c @@ -0,0 +1,313 @@ +/* + * userio kernel serio device emulation module + * Copyright (C) 2015 Red Hat + * Copyright (C) 2015 Lyude Paul + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser + * General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define USERIO_NAME "userio" +#define USERIO_BUFSIZE 16 + +static struct miscdevice userio_misc; + +struct userio_device { + struct serio *serio; + struct mutex mutex; + + bool running; + + u8 head; + u8 tail; + + spinlock_t buf_lock; + unsigned char buf[USERIO_BUFSIZE]; + + wait_queue_head_t waitq; +}; + +/** + * userio_device_write - Write data from serio to a userio device in userspace + * @id: The serio port for the userio device + * @val: The data to write to the device + */ +static int userio_device_write(struct serio *id, unsigned char val) +{ + struct userio_device *userio = id->port_data; + + scoped_guard(spinlock_irqsave, &userio->buf_lock) { + userio->buf[userio->head] = val; + userio->head = (userio->head + 1) % USERIO_BUFSIZE; + + if (userio->head == userio->tail) + dev_warn(userio_misc.this_device, + "Buffer overflowed, userio client isn't keeping up"); + } + + wake_up_interruptible(&userio->waitq); + + return 0; +} + +static int userio_char_open(struct inode *inode, struct file *file) +{ + struct userio_device *userio __free(kfree) = + kzalloc_obj(*userio); + if (!userio) + return -ENOMEM; + + mutex_init(&userio->mutex); + spin_lock_init(&userio->buf_lock); + init_waitqueue_head(&userio->waitq); + + userio->serio = kzalloc_obj(*userio->serio); + if (!userio->serio) + return -ENOMEM; + + userio->serio->write = userio_device_write; + userio->serio->port_data = userio; + + file->private_data = no_free_ptr(userio); + + return 0; +} + +static int userio_char_release(struct inode *inode, struct file *file) +{ + struct userio_device *userio = file->private_data; + + if (userio->running) { + /* + * Don't free the serio port here, serio_unregister_port() + * does it for us. + */ + serio_unregister_port(userio->serio); + } else { + kfree(userio->serio); + } + + kfree(userio); + + return 0; +} + +static size_t userio_fetch_data(struct userio_device *userio, u8 *buf, + size_t count, size_t *copylen) +{ + size_t available, len; + + guard(spinlock_irqsave)(&userio->buf_lock); + + available = CIRC_CNT_TO_END(userio->head, userio->tail, + USERIO_BUFSIZE); + len = min(available, count); + if (len) { + memcpy(buf, &userio->buf[userio->tail], len); + userio->tail = (userio->tail + len) % USERIO_BUFSIZE; + } + + *copylen = len; + return available; +} + +static ssize_t userio_char_read(struct file *file, char __user *user_buffer, + size_t count, loff_t *ppos) +{ + struct userio_device *userio = file->private_data; + int error; + size_t available, copylen; + u8 buf[USERIO_BUFSIZE]; + + /* + * By the time we get here, the data that was waiting might have + * been taken by another thread. Grab the buffer lock and check if + * there's still any data waiting, otherwise repeat this process + * until we have data (unless the file descriptor is non-blocking + * of course). + */ + for (;;) { + available = userio_fetch_data(userio, buf, count, ©len); + if (available) + break; + + /* buffer was/is empty */ + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + /* + * count == 0 is special - no IO is done but we check + * for error conditions (see above). + */ + if (count == 0) + return 0; + + error = wait_event_interruptible(userio->waitq, + userio->head != userio->tail); + if (error) + return error; + } + + if (copylen) + if (copy_to_user(user_buffer, buf, copylen)) + return -EFAULT; + + return copylen; +} + +static int userio_execute_cmd(struct userio_device *userio, + const struct userio_cmd *cmd) +{ + switch (cmd->type) { + case USERIO_CMD_REGISTER: + if (!userio->serio->id.type) { + dev_warn(userio_misc.this_device, + "No port type given on /dev/userio\n"); + return -EINVAL; + } + + if (userio->running) { + dev_warn(userio_misc.this_device, + "Begin command sent, but we're already running\n"); + return -EBUSY; + } + + userio->running = true; + serio_register_port(userio->serio); + break; + + case USERIO_CMD_SET_PORT_TYPE: + if (userio->running) { + dev_warn(userio_misc.this_device, + "Can't change port type on an already running userio instance\n"); + return -EBUSY; + } + + userio->serio->id.type = cmd->data; + break; + + case USERIO_CMD_SET_PORT_EXTRA: + if (userio->running) { + dev_warn(userio_misc.this_device, + "Can't change port extra on an already running userio instance\n"); + return -EBUSY; + } + + userio->serio->id.extra = cmd->data; + break; + + case USERIO_CMD_SET_PORT_ID: + if (userio->running) { + dev_warn(userio_misc.this_device, + "Can't change port id on an already running userio instance\n"); + return -EBUSY; + } + + userio->serio->id.id = cmd->data; + break; + + case USERIO_CMD_SET_PORT_PROTO: + if (userio->running) { + dev_warn(userio_misc.this_device, + "Can't change port proto on an already running userio instance\n"); + return -EBUSY; + } + + userio->serio->id.proto = cmd->data; + break; + + case USERIO_CMD_SEND_INTERRUPT: + if (!userio->running) { + dev_warn(userio_misc.this_device, + "The device must be registered before sending interrupts\n"); + return -ENODEV; + } + + serio_interrupt(userio->serio, cmd->data, 0); + break; + + default: + return -EOPNOTSUPP; + } + + return 0; +} + +static ssize_t userio_char_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + struct userio_device *userio = file->private_data; + struct userio_cmd cmd; + int error; + + if (count != sizeof(cmd)) { + dev_warn(userio_misc.this_device, "Invalid payload size\n"); + return -EINVAL; + } + + if (copy_from_user(&cmd, buffer, sizeof(cmd))) + return -EFAULT; + + scoped_cond_guard(mutex_intr, return -EINTR, &userio->mutex) { + error = userio_execute_cmd(userio, &cmd); + if (error) + return error; + } + + return count; +} + +static __poll_t userio_char_poll(struct file *file, poll_table *wait) +{ + struct userio_device *userio = file->private_data; + + poll_wait(file, &userio->waitq, wait); + + if (userio->head != userio->tail) + return EPOLLIN | EPOLLRDNORM; + + return 0; +} + +static const struct file_operations userio_fops = { + .owner = THIS_MODULE, + .open = userio_char_open, + .release = userio_char_release, + .read = userio_char_read, + .write = userio_char_write, + .poll = userio_char_poll, +}; + +static struct miscdevice userio_misc = { + .fops = &userio_fops, + .minor = USERIO_MINOR, + .name = USERIO_NAME, +}; +module_driver(userio_misc, misc_register, misc_deregister); + +MODULE_ALIAS_MISCDEV(USERIO_MINOR); +MODULE_ALIAS("devname:" USERIO_NAME); + +MODULE_AUTHOR("Lyude Paul "); +MODULE_DESCRIPTION("Virtual Serio Device Support"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1