Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

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

1 files changed, 576 insertions, 0 deletions

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 <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/compat.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/sched/signal.h>
+#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(&param, 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, &param);
+			else
+				err = -EINVAL;
+		}
+
+		if (!err)
+			if (copy_to_user(uarg, &param, sizeof(param)))
+				err = -EFAULT;
+
+		break;
+
+	case RTC_PARAM_SET:
+		if (copy_from_user(&param, 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, &param);
+			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");
+}