From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- drivers/rtc/dev.c | 576 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 576 insertions(+) create mode 100644 drivers/rtc/dev.c (limited to 'drivers/rtc/dev.c') diff --git a/drivers/rtc/dev.c b/drivers/rtc/dev.c new file mode 100644 index 000000000..8ba7c25d2 --- /dev/null +++ b/drivers/rtc/dev.c @@ -0,0 +1,576 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * RTC subsystem, dev interface + * + * Copyright (C) 2005 Tower Technologies + * Author: Alessandro Zummo + * + * based on arch/arm/common/rtctime.c + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include "rtc-core.h" + +static dev_t rtc_devt; + +#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */ + +static int rtc_dev_open(struct inode *inode, struct file *file) +{ + struct rtc_device *rtc = container_of(inode->i_cdev, + struct rtc_device, char_dev); + + if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) + return -EBUSY; + + file->private_data = rtc; + + spin_lock_irq(&rtc->irq_lock); + rtc->irq_data = 0; + spin_unlock_irq(&rtc->irq_lock); + + return 0; +} + +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL +/* + * Routine to poll RTC seconds field for change as often as possible, + * after first RTC_UIE use timer to reduce polling + */ +static void rtc_uie_task(struct work_struct *work) +{ + struct rtc_device *rtc = + container_of(work, struct rtc_device, uie_task); + struct rtc_time tm; + int num = 0; + int err; + + err = rtc_read_time(rtc, &tm); + + spin_lock_irq(&rtc->irq_lock); + if (rtc->stop_uie_polling || err) { + rtc->uie_task_active = 0; + } else if (rtc->oldsecs != tm.tm_sec) { + num = (tm.tm_sec + 60 - rtc->oldsecs) % 60; + rtc->oldsecs = tm.tm_sec; + rtc->uie_timer.expires = jiffies + HZ - (HZ / 10); + rtc->uie_timer_active = 1; + rtc->uie_task_active = 0; + add_timer(&rtc->uie_timer); + } else if (schedule_work(&rtc->uie_task) == 0) { + rtc->uie_task_active = 0; + } + spin_unlock_irq(&rtc->irq_lock); + if (num) + rtc_handle_legacy_irq(rtc, num, RTC_UF); +} + +static void rtc_uie_timer(struct timer_list *t) +{ + struct rtc_device *rtc = timer_container_of(rtc, t, uie_timer); + unsigned long flags; + + spin_lock_irqsave(&rtc->irq_lock, flags); + rtc->uie_timer_active = 0; + rtc->uie_task_active = 1; + if ((schedule_work(&rtc->uie_task) == 0)) + rtc->uie_task_active = 0; + spin_unlock_irqrestore(&rtc->irq_lock, flags); +} + +static int clear_uie(struct rtc_device *rtc) +{ + spin_lock_irq(&rtc->irq_lock); + if (rtc->uie_irq_active) { + rtc->stop_uie_polling = 1; + if (rtc->uie_timer_active) { + spin_unlock_irq(&rtc->irq_lock); + timer_delete_sync(&rtc->uie_timer); + spin_lock_irq(&rtc->irq_lock); + rtc->uie_timer_active = 0; + } + if (rtc->uie_task_active) { + spin_unlock_irq(&rtc->irq_lock); + flush_work(&rtc->uie_task); + spin_lock_irq(&rtc->irq_lock); + } + rtc->uie_irq_active = 0; + } + spin_unlock_irq(&rtc->irq_lock); + return 0; +} + +static int set_uie(struct rtc_device *rtc) +{ + struct rtc_time tm; + int err; + + err = rtc_read_time(rtc, &tm); + if (err) + return err; + spin_lock_irq(&rtc->irq_lock); + if (!rtc->uie_irq_active) { + rtc->uie_irq_active = 1; + rtc->stop_uie_polling = 0; + rtc->oldsecs = tm.tm_sec; + rtc->uie_task_active = 1; + if (schedule_work(&rtc->uie_task) == 0) + rtc->uie_task_active = 0; + } + rtc->irq_data = 0; + spin_unlock_irq(&rtc->irq_lock); + return 0; +} + +int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled) +{ + if (enabled) + return set_uie(rtc); + else + return clear_uie(rtc); +} +EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul); + +#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */ + +static ssize_t +rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + struct rtc_device *rtc = file->private_data; + + DECLARE_WAITQUEUE(wait, current); + unsigned long data; + ssize_t ret; + + if (count != sizeof(unsigned int) && count < sizeof(unsigned long)) + return -EINVAL; + + add_wait_queue(&rtc->irq_queue, &wait); + do { + __set_current_state(TASK_INTERRUPTIBLE); + + spin_lock_irq(&rtc->irq_lock); + data = rtc->irq_data; + rtc->irq_data = 0; + spin_unlock_irq(&rtc->irq_lock); + + if (data != 0) { + ret = 0; + break; + } + if (file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + break; + } + if (signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + schedule(); + } while (1); + set_current_state(TASK_RUNNING); + remove_wait_queue(&rtc->irq_queue, &wait); + + if (ret == 0) { + if (sizeof(int) != sizeof(long) && + count == sizeof(unsigned int)) + ret = put_user(data, (unsigned int __user *)buf) ?: + sizeof(unsigned int); + else + ret = put_user(data, (unsigned long __user *)buf) ?: + sizeof(unsigned long); + } + return ret; +} + +static __poll_t rtc_dev_poll(struct file *file, poll_table *wait) +{ + struct rtc_device *rtc = file->private_data; + unsigned long data; + + poll_wait(file, &rtc->irq_queue, wait); + + /* + * This read can race with the write in rtc_handle_legacy_irq(). + * + * - If this check misses a zero to non-zero transition the next check + * will pick it up (rtc_handle_legacy_irq() wakes up rtc->irq_queue). + * - Non-zero to non-zero transition misses do not change return value. + * - And a non-zero to zero transition is unlikely to be missed, since + * it occurs on rtc_dev_read(), during which polling is not expected. + */ + data = data_race(rtc->irq_data); + + return (data != 0) ? (EPOLLIN | EPOLLRDNORM) : 0; +} + +static long rtc_dev_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + int err = 0; + struct rtc_device *rtc = file->private_data; + const struct rtc_class_ops *ops = rtc->ops; + struct rtc_time tm; + struct rtc_wkalrm alarm; + struct rtc_param param; + void __user *uarg = (void __user *)arg; + + err = mutex_lock_interruptible(&rtc->ops_lock); + if (err) + return err; + + /* check that the calling task has appropriate permissions + * for certain ioctls. doing this check here is useful + * to avoid duplicate code in each driver. + */ + switch (cmd) { + case RTC_EPOCH_SET: + case RTC_SET_TIME: + case RTC_PARAM_SET: + if (!capable(CAP_SYS_TIME)) + err = -EACCES; + break; + + case RTC_IRQP_SET: + if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE)) + err = -EACCES; + break; + + case RTC_PIE_ON: + if (rtc->irq_freq > rtc->max_user_freq && + !capable(CAP_SYS_RESOURCE)) + err = -EACCES; + break; + } + + if (err) + goto done; + + /* + * Drivers *SHOULD NOT* provide ioctl implementations + * for these requests. Instead, provide methods to + * support the following code, so that the RTC's main + * features are accessible without using ioctls. + * + * RTC and alarm times will be in UTC, by preference, + * but dual-booting with MS-Windows implies RTCs must + * use the local wall clock time. + */ + + switch (cmd) { + case RTC_ALM_READ: + mutex_unlock(&rtc->ops_lock); + + err = rtc_read_alarm(rtc, &alarm); + if (err < 0) + return err; + + if (copy_to_user(uarg, &alarm.time, sizeof(tm))) + err = -EFAULT; + return err; + + case RTC_ALM_SET: + mutex_unlock(&rtc->ops_lock); + + if (copy_from_user(&alarm.time, uarg, sizeof(tm))) + return -EFAULT; + + alarm.enabled = 0; + alarm.pending = 0; + alarm.time.tm_wday = -1; + alarm.time.tm_yday = -1; + alarm.time.tm_isdst = -1; + + /* RTC_ALM_SET alarms may be up to 24 hours in the future. + * Rather than expecting every RTC to implement "don't care" + * for day/month/year fields, just force the alarm to have + * the right values for those fields. + * + * RTC_WKALM_SET should be used instead. Not only does it + * eliminate the need for a separate RTC_AIE_ON call, it + * doesn't have the "alarm 23:59:59 in the future" race. + * + * NOTE: some legacy code may have used invalid fields as + * wildcards, exposing hardware "periodic alarm" capabilities. + * Not supported here. + */ + { + time64_t now, then; + + err = rtc_read_time(rtc, &tm); + if (err < 0) + return err; + now = rtc_tm_to_time64(&tm); + + alarm.time.tm_mday = tm.tm_mday; + alarm.time.tm_mon = tm.tm_mon; + alarm.time.tm_year = tm.tm_year; + err = rtc_valid_tm(&alarm.time); + if (err < 0) + return err; + then = rtc_tm_to_time64(&alarm.time); + + /* alarm may need to wrap into tomorrow */ + if (then < now) { + rtc_time64_to_tm(now + 24 * 60 * 60, &tm); + alarm.time.tm_mday = tm.tm_mday; + alarm.time.tm_mon = tm.tm_mon; + alarm.time.tm_year = tm.tm_year; + } + } + + return rtc_set_alarm(rtc, &alarm); + + case RTC_RD_TIME: + mutex_unlock(&rtc->ops_lock); + + err = rtc_read_time(rtc, &tm); + if (err < 0) + return err; + + if (copy_to_user(uarg, &tm, sizeof(tm))) + err = -EFAULT; + return err; + + case RTC_SET_TIME: + mutex_unlock(&rtc->ops_lock); + + if (copy_from_user(&tm, uarg, sizeof(tm))) + return -EFAULT; + + return rtc_set_time(rtc, &tm); + + case RTC_PIE_ON: + err = rtc_irq_set_state(rtc, 1); + break; + + case RTC_PIE_OFF: + err = rtc_irq_set_state(rtc, 0); + break; + + case RTC_AIE_ON: + mutex_unlock(&rtc->ops_lock); + return rtc_alarm_irq_enable(rtc, 1); + + case RTC_AIE_OFF: + mutex_unlock(&rtc->ops_lock); + return rtc_alarm_irq_enable(rtc, 0); + + case RTC_UIE_ON: + mutex_unlock(&rtc->ops_lock); + return rtc_update_irq_enable(rtc, 1); + + case RTC_UIE_OFF: + mutex_unlock(&rtc->ops_lock); + return rtc_update_irq_enable(rtc, 0); + + case RTC_IRQP_SET: + err = rtc_irq_set_freq(rtc, arg); + break; + case RTC_IRQP_READ: + err = put_user(rtc->irq_freq, (unsigned long __user *)uarg); + break; + + case RTC_WKALM_SET: + mutex_unlock(&rtc->ops_lock); + if (copy_from_user(&alarm, uarg, sizeof(alarm))) + return -EFAULT; + + return rtc_set_alarm(rtc, &alarm); + + case RTC_WKALM_RD: + mutex_unlock(&rtc->ops_lock); + err = rtc_read_alarm(rtc, &alarm); + if (err < 0) + return err; + + if (copy_to_user(uarg, &alarm, sizeof(alarm))) + err = -EFAULT; + return err; + + case RTC_PARAM_GET: + if (copy_from_user(¶m, uarg, sizeof(param))) { + mutex_unlock(&rtc->ops_lock); + return -EFAULT; + } + + switch(param.param) { + case RTC_PARAM_FEATURES: + if (param.index != 0) + err = -EINVAL; + param.uvalue = rtc->features[0]; + break; + + case RTC_PARAM_CORRECTION: { + long offset; + mutex_unlock(&rtc->ops_lock); + if (param.index != 0) + return -EINVAL; + err = rtc_read_offset(rtc, &offset); + mutex_lock(&rtc->ops_lock); + if (err == 0) + param.svalue = offset; + break; + } + default: + if (rtc->ops->param_get) + err = rtc->ops->param_get(rtc->dev.parent, ¶m); + else + err = -EINVAL; + } + + if (!err) + if (copy_to_user(uarg, ¶m, sizeof(param))) + err = -EFAULT; + + break; + + case RTC_PARAM_SET: + if (copy_from_user(¶m, uarg, sizeof(param))) { + mutex_unlock(&rtc->ops_lock); + return -EFAULT; + } + + switch(param.param) { + case RTC_PARAM_FEATURES: + err = -EINVAL; + break; + + case RTC_PARAM_CORRECTION: + mutex_unlock(&rtc->ops_lock); + if (param.index != 0) + return -EINVAL; + return rtc_set_offset(rtc, param.svalue); + + default: + if (rtc->ops->param_set) + err = rtc->ops->param_set(rtc->dev.parent, ¶m); + else + err = -EINVAL; + } + + break; + + default: + /* Finally try the driver's ioctl interface */ + if (ops->ioctl) { + err = ops->ioctl(rtc->dev.parent, cmd, arg); + if (err == -ENOIOCTLCMD) + err = -ENOTTY; + } else { + err = -ENOTTY; + } + break; + } + +done: + mutex_unlock(&rtc->ops_lock); + return err; +} + +#ifdef CONFIG_COMPAT +#define RTC_IRQP_SET32 _IOW('p', 0x0c, __u32) +#define RTC_IRQP_READ32 _IOR('p', 0x0b, __u32) +#define RTC_EPOCH_SET32 _IOW('p', 0x0e, __u32) + +static long rtc_dev_compat_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct rtc_device *rtc = file->private_data; + void __user *uarg = compat_ptr(arg); + + switch (cmd) { + case RTC_IRQP_READ32: + return put_user(rtc->irq_freq, (__u32 __user *)uarg); + + case RTC_IRQP_SET32: + /* arg is a plain integer, not pointer */ + return rtc_dev_ioctl(file, RTC_IRQP_SET, arg); + + case RTC_EPOCH_SET32: + /* arg is a plain integer, not pointer */ + return rtc_dev_ioctl(file, RTC_EPOCH_SET, arg); + } + + return rtc_dev_ioctl(file, cmd, (unsigned long)uarg); +} +#endif + +static int rtc_dev_fasync(int fd, struct file *file, int on) +{ + struct rtc_device *rtc = file->private_data; + + return fasync_helper(fd, file, on, &rtc->async_queue); +} + +static int rtc_dev_release(struct inode *inode, struct file *file) +{ + struct rtc_device *rtc = file->private_data; + + /* We shut down the repeating IRQs that userspace enabled, + * since nothing is listening to them. + * - Update (UIE) ... currently only managed through ioctls + * - Periodic (PIE) ... also used through rtc_*() interface calls + * + * Leave the alarm alone; it may be set to trigger a system wakeup + * later, or be used by kernel code, and is a one-shot event anyway. + */ + + /* Keep ioctl until all drivers are converted */ + rtc_dev_ioctl(file, RTC_UIE_OFF, 0); + rtc_update_irq_enable(rtc, 0); + rtc_irq_set_state(rtc, 0); + + clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); + return 0; +} + +static const struct file_operations rtc_dev_fops = { + .owner = THIS_MODULE, + .read = rtc_dev_read, + .poll = rtc_dev_poll, + .unlocked_ioctl = rtc_dev_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = rtc_dev_compat_ioctl, +#endif + .open = rtc_dev_open, + .release = rtc_dev_release, + .fasync = rtc_dev_fasync, +}; + +/* insertion/removal hooks */ + +void rtc_dev_prepare(struct rtc_device *rtc) +{ + if (!rtc_devt) + return; + + if (rtc->id >= RTC_DEV_MAX) { + dev_dbg(&rtc->dev, "too many RTC devices\n"); + return; + } + + rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id); + +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL + INIT_WORK(&rtc->uie_task, rtc_uie_task); + timer_setup(&rtc->uie_timer, rtc_uie_timer, 0); +#endif + + cdev_init(&rtc->char_dev, &rtc_dev_fops); + rtc->char_dev.owner = rtc->owner; +} + +void __init rtc_dev_init(void) +{ + int err; + + err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc"); + if (err < 0) + pr_err("failed to allocate char dev region\n"); +} -- cgit v1.3.1