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, 645 insertions, 0 deletions

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
new file mode 100644
index 000000000..709a24092
--- /dev/null
+++ b/drivers/usb/usb-skeleton.c
@@ -0,0 +1,645 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Skeleton driver - 2.2
+ *
+ * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
+ * but has been rewritten to be easier to read and use.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kref.h>
+#include <linux/uaccess.h>
+#include <linux/usb.h>
+#include <linux/mutex.h>
+
+
+/* Define these values to match your devices */
+#define USB_SKEL_VENDOR_ID	0xfff0
+#define USB_SKEL_PRODUCT_ID	0xfff0
+
+/* table of devices that work with this driver */
+static const struct usb_device_id skel_table[] = {
+	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
+	{ }					/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, skel_table);
+
+
+/* Get a minor range for your devices from the usb maintainer */
+#define USB_SKEL_MINOR_BASE	192
+
+/* our private defines. if this grows any larger, use your own .h file */
+#define MAX_TRANSFER		(PAGE_SIZE - 512)
+/*
+ * MAX_TRANSFER is chosen so that the VM is not stressed by
+ * allocations > PAGE_SIZE and the number of packets in a page
+ * is an integer 512 is the largest possible packet on EHCI
+ */
+#define WRITES_IN_FLIGHT	8
+/* arbitrarily chosen */
+
+/* Structure to hold all of our device specific stuff */
+struct usb_skel {
+	struct usb_device	*udev;			/* the usb device for this device */
+	struct usb_interface	*interface;		/* the interface for this device */
+	struct semaphore	limit_sem;		/* limiting the number of writes in progress */
+	struct usb_anchor	submitted;		/* in case we need to retract our submissions */
+	struct urb		*bulk_in_urb;		/* the urb to read data with */
+	unsigned char           *bulk_in_buffer;	/* the buffer to receive data */
+	size_t			bulk_in_size;		/* the size of the receive buffer */
+	size_t			bulk_in_filled;		/* number of bytes in the buffer */
+	size_t			bulk_in_copied;		/* already copied to user space */
+	__u8			bulk_in_endpointAddr;	/* the address of the bulk in endpoint */
+	__u8			bulk_out_endpointAddr;	/* the address of the bulk out endpoint */
+	int			errors;			/* the last request tanked */
+	bool			ongoing_read;		/* a read is going on */
+	spinlock_t		err_lock;		/* lock for errors */
+	struct kref		kref;
+	struct mutex		io_mutex;		/* synchronize I/O with disconnect */
+	unsigned long		disconnected:1;
+	wait_queue_head_t	bulk_in_wait;		/* to wait for an ongoing read */
+};
+#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
+
+static struct usb_driver skel_driver;
+static void skel_draw_down(struct usb_skel *dev);
+
+static void skel_delete(struct kref *kref)
+{
+	struct usb_skel *dev = to_skel_dev(kref);
+
+	usb_free_urb(dev->bulk_in_urb);
+	usb_put_intf(dev->interface);
+	usb_put_dev(dev->udev);
+	kfree(dev->bulk_in_buffer);
+	kfree(dev);
+}
+
+static int skel_open(struct inode *inode, struct file *file)
+{
+	struct usb_skel *dev;
+	struct usb_interface *interface;
+	int subminor;
+	int retval = 0;
+
+	subminor = iminor(inode);
+
+	interface = usb_find_interface(&skel_driver, subminor);
+	if (!interface) {
+		pr_err("%s - error, can't find device for minor %d\n",
+			__func__, subminor);
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	retval = usb_autopm_get_interface(interface);
+	if (retval)
+		goto exit;
+
+	/* increment our usage count for the device */
+	kref_get(&dev->kref);
+
+	/* save our object in the file's private structure */
+	file->private_data = dev;
+
+exit:
+	return retval;
+}
+
+static int skel_release(struct inode *inode, struct file *file)
+{
+	struct usb_skel *dev;
+
+	dev = file->private_data;
+	if (dev == NULL)
+		return -ENODEV;
+
+	/* allow the device to be autosuspended */
+	usb_autopm_put_interface(dev->interface);
+
+	/* decrement the count on our device */
+	kref_put(&dev->kref, skel_delete);
+	return 0;
+}
+
+static int skel_flush(struct file *file, fl_owner_t id)
+{
+	struct usb_skel *dev;
+	int res;
+
+	dev = file->private_data;
+	if (dev == NULL)
+		return -ENODEV;
+
+	/* wait for io to stop */
+	mutex_lock(&dev->io_mutex);
+	skel_draw_down(dev);
+
+	/* read out errors, leave subsequent opens a clean slate */
+	spin_lock_irq(&dev->err_lock);
+	res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
+	dev->errors = 0;
+	spin_unlock_irq(&dev->err_lock);
+
+	mutex_unlock(&dev->io_mutex);
+
+	return res;
+}
+
+static void skel_read_bulk_callback(struct urb *urb)
+{
+	struct usb_skel *dev;
+	unsigned long flags;
+
+	dev = urb->context;
+
+	spin_lock_irqsave(&dev->err_lock, flags);
+	/* sync/async unlink faults aren't errors */
+	if (urb->status) {
+		if (!(urb->status == -ENOENT ||
+		    urb->status == -ECONNRESET ||
+		    urb->status == -ESHUTDOWN))
+			dev_err(&dev->interface->dev,
+				"%s - nonzero write bulk status received: %d\n",
+				__func__, urb->status);
+
+		dev->errors = urb->status;
+	} else {
+		dev->bulk_in_filled = urb->actual_length;
+	}
+	dev->ongoing_read = 0;
+	spin_unlock_irqrestore(&dev->err_lock, flags);
+
+	wake_up_interruptible(&dev->bulk_in_wait);
+}
+
+static int skel_do_read_io(struct usb_skel *dev, size_t count)
+{
+	int rv;
+
+	/* prepare a read */
+	usb_fill_bulk_urb(dev->bulk_in_urb,
+			dev->udev,
+			usb_rcvbulkpipe(dev->udev,
+				dev->bulk_in_endpointAddr),
+			dev->bulk_in_buffer,
+			min(dev->bulk_in_size, count),
+			skel_read_bulk_callback,
+			dev);
+	/* tell everybody to leave the URB alone */
+	spin_lock_irq(&dev->err_lock);
+	dev->ongoing_read = 1;
+	spin_unlock_irq(&dev->err_lock);
+
+	/* submit bulk in urb, which means no data to deliver */
+	dev->bulk_in_filled = 0;
+	dev->bulk_in_copied = 0;
+
+	/* do it */
+	rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
+	if (rv < 0) {
+		dev_err(&dev->interface->dev,
+			"%s - failed submitting read urb, error %d\n",
+			__func__, rv);
+		rv = (rv == -ENOMEM) ? rv : -EIO;
+		spin_lock_irq(&dev->err_lock);
+		dev->ongoing_read = 0;
+		spin_unlock_irq(&dev->err_lock);
+	}
+
+	return rv;
+}
+
+static ssize_t skel_read(struct file *file, char *buffer, size_t count,
+			 loff_t *ppos)
+{
+	struct usb_skel *dev;
+	int rv;
+	bool ongoing_io;
+
+	dev = file->private_data;
+
+	if (!count)
+		return 0;
+
+	/* no concurrent readers */
+	rv = mutex_lock_interruptible(&dev->io_mutex);
+	if (rv < 0)
+		return rv;
+
+	if (dev->disconnected) {		/* disconnect() was called */
+		rv = -ENODEV;
+		goto exit;
+	}
+
+	/* if IO is under way, we must not touch things */
+retry:
+	spin_lock_irq(&dev->err_lock);
+	ongoing_io = dev->ongoing_read;
+	spin_unlock_irq(&dev->err_lock);
+
+	if (ongoing_io) {
+		/* nonblocking IO shall not wait */
+		if (file->f_flags & O_NONBLOCK) {
+			rv = -EAGAIN;
+			goto exit;
+		}
+		/*
+		 * IO may take forever
+		 * hence wait in an interruptible state
+		 */
+		rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read));
+		if (rv < 0)
+			goto exit;
+	}
+
+	/* errors must be reported */
+	rv = dev->errors;
+	if (rv < 0) {
+		/* any error is reported once */
+		dev->errors = 0;
+		/* to preserve notifications about reset */
+		rv = (rv == -EPIPE) ? rv : -EIO;
+		/* report it */
+		goto exit;
+	}
+
+	/*
+	 * if the buffer is filled we may satisfy the read
+	 * else we need to start IO
+	 */
+
+	if (dev->bulk_in_filled) {
+		/* we had read data */
+		size_t available = dev->bulk_in_filled - dev->bulk_in_copied;
+		size_t chunk = min(available, count);
+
+		if (!available) {
+			/*
+			 * all data has been used
+			 * actual IO needs to be done
+			 */
+			rv = skel_do_read_io(dev, count);
+			if (rv < 0)
+				goto exit;
+			else
+				goto retry;
+		}
+		/*
+		 * data is available
+		 * chunk tells us how much shall be copied
+		 */
+
+		if (copy_to_user(buffer,
+				 dev->bulk_in_buffer + dev->bulk_in_copied,
+				 chunk))
+			rv = -EFAULT;
+		else
+			rv = chunk;
+
+		dev->bulk_in_copied += chunk;
+
+		/*
+		 * if we are asked for more than we have,
+		 * we start IO but don't wait
+		 */
+		if (available < count)
+			skel_do_read_io(dev, count - chunk);
+	} else {
+		/* no data in the buffer */
+		rv = skel_do_read_io(dev, count);
+		if (rv < 0)
+			goto exit;
+		else
+			goto retry;
+	}
+exit:
+	mutex_unlock(&dev->io_mutex);
+	return rv;
+}
+
+static void skel_write_bulk_callback(struct urb *urb)
+{
+	struct usb_skel *dev;
+	unsigned long flags;
+
+	dev = urb->context;
+
+	/* sync/async unlink faults aren't errors */
+	if (urb->status) {
+		if (!(urb->status == -ENOENT ||
+		    urb->status == -ECONNRESET ||
+		    urb->status == -ESHUTDOWN))
+			dev_err(&dev->interface->dev,
+				"%s - nonzero write bulk status received: %d\n",
+				__func__, urb->status);
+
+		spin_lock_irqsave(&dev->err_lock, flags);
+		dev->errors = urb->status;
+		spin_unlock_irqrestore(&dev->err_lock, flags);
+	}
+
+	/* free up our allocated buffer */
+	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+			  urb->transfer_buffer, urb->transfer_dma);
+	up(&dev->limit_sem);
+}
+
+static ssize_t skel_write(struct file *file, const char *user_buffer,
+			  size_t count, loff_t *ppos)
+{
+	struct usb_skel *dev;
+	int retval = 0;
+	struct urb *urb = NULL;
+	char *buf = NULL;
+	size_t writesize = min_t(size_t, count, MAX_TRANSFER);
+
+	dev = file->private_data;
+
+	/* verify that we actually have some data to write */
+	if (count == 0)
+		goto exit;
+
+	/*
+	 * limit the number of URBs in flight to stop a user from using up all
+	 * RAM
+	 */
+	if (!(file->f_flags & O_NONBLOCK)) {
+		if (down_interruptible(&dev->limit_sem)) {
+			retval = -ERESTARTSYS;
+			goto exit;
+		}
+	} else {
+		if (down_trylock(&dev->limit_sem)) {
+			retval = -EAGAIN;
+			goto exit;
+		}
+	}
+
+	spin_lock_irq(&dev->err_lock);
+	retval = dev->errors;
+	if (retval < 0) {
+		/* any error is reported once */
+		dev->errors = 0;
+		/* to preserve notifications about reset */
+		retval = (retval == -EPIPE) ? retval : -EIO;
+	}
+	spin_unlock_irq(&dev->err_lock);
+	if (retval < 0)
+		goto error;
+
+	/* create a urb, and a buffer for it, and copy the data to the urb */
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL,
+				 &urb->transfer_dma);
+	if (!buf) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	if (copy_from_user(buf, user_buffer, writesize)) {
+		retval = -EFAULT;
+		goto error;
+	}
+
+	/* this lock makes sure we don't submit URBs to gone devices */
+	mutex_lock(&dev->io_mutex);
+	if (dev->disconnected) {		/* disconnect() was called */
+		mutex_unlock(&dev->io_mutex);
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* initialize the urb properly */
+	usb_fill_bulk_urb(urb, dev->udev,
+			  usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
+			  buf, writesize, skel_write_bulk_callback, dev);
+	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	usb_anchor_urb(urb, &dev->submitted);
+
+	/* send the data out the bulk port */
+	retval = usb_submit_urb(urb, GFP_KERNEL);
+	mutex_unlock(&dev->io_mutex);
+	if (retval) {
+		dev_err(&dev->interface->dev,
+			"%s - failed submitting write urb, error %d\n",
+			__func__, retval);
+		goto error_unanchor;
+	}
+
+	/*
+	 * release our reference to this urb, the USB core will eventually free
+	 * it entirely
+	 */
+	usb_free_urb(urb);
+
+
+	return writesize;
+
+error_unanchor:
+	usb_unanchor_urb(urb);
+error:
+	if (urb) {
+		usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);
+		usb_free_urb(urb);
+	}
+	up(&dev->limit_sem);
+
+exit:
+	return retval;
+}
+
+static const struct file_operations skel_fops = {
+	.owner =	THIS_MODULE,
+	.read =		skel_read,
+	.write =	skel_write,
+	.open =		skel_open,
+	.release =	skel_release,
+	.flush =	skel_flush,
+	.llseek =	noop_llseek,
+};
+
+/*
+ * usb class driver info in order to get a minor number from the usb core,
+ * and to have the device registered with the driver core
+ */
+static struct usb_class_driver skel_class = {
+	.name =		"skel%d",
+	.fops =		&skel_fops,
+	.minor_base =	USB_SKEL_MINOR_BASE,
+};
+
+static int skel_probe(struct usb_interface *interface,
+		      const struct usb_device_id *id)
+{
+	struct usb_skel *dev;
+	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
+	int retval;
+
+	/* allocate memory for our device state and initialize it */
+	dev = kzalloc_obj(*dev);
+	if (!dev)
+		return -ENOMEM;
+
+	kref_init(&dev->kref);
+	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
+	mutex_init(&dev->io_mutex);
+	spin_lock_init(&dev->err_lock);
+	init_usb_anchor(&dev->submitted);
+	init_waitqueue_head(&dev->bulk_in_wait);
+
+	dev->udev = usb_get_dev(interface_to_usbdev(interface));
+	dev->interface = usb_get_intf(interface);
+
+	/* set up the endpoint information */
+	/* use only the first bulk-in and bulk-out endpoints */
+	retval = usb_find_common_endpoints(interface->cur_altsetting,
+			&bulk_in, &bulk_out, NULL, NULL);
+	if (retval) {
+		dev_err(&interface->dev,
+			"Could not find both bulk-in and bulk-out endpoints\n");
+		goto error;
+	}
+
+	dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
+	dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
+	dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
+	if (!dev->bulk_in_buffer) {
+		retval = -ENOMEM;
+		goto error;
+	}
+	dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->bulk_in_urb) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
+
+	/* save our data pointer in this interface device */
+	usb_set_intfdata(interface, dev);
+
+	/* we can register the device now, as it is ready */
+	retval = usb_register_dev(interface, &skel_class);
+	if (retval) {
+		/* something prevented us from registering this driver */
+		dev_err(&interface->dev,
+			"Not able to get a minor for this device.\n");
+		usb_set_intfdata(interface, NULL);
+		goto error;
+	}
+
+	/* let the user know what node this device is now attached to */
+	dev_info(&interface->dev,
+		 "USB Skeleton device now attached to USBSkel-%d",
+		 interface->minor);
+	return 0;
+
+error:
+	/* this frees allocated memory */
+	kref_put(&dev->kref, skel_delete);
+
+	return retval;
+}
+
+static void skel_disconnect(struct usb_interface *interface)
+{
+	struct usb_skel *dev;
+	int minor = interface->minor;
+
+	dev = usb_get_intfdata(interface);
+
+	/* give back our minor */
+	usb_deregister_dev(interface, &skel_class);
+
+	/* prevent more I/O from starting */
+	mutex_lock(&dev->io_mutex);
+	dev->disconnected = 1;
+	mutex_unlock(&dev->io_mutex);
+
+	usb_kill_urb(dev->bulk_in_urb);
+	usb_kill_anchored_urbs(&dev->submitted);
+
+	/* decrement our usage count */
+	kref_put(&dev->kref, skel_delete);
+
+	dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);
+}
+
+static void skel_draw_down(struct usb_skel *dev)
+{
+	int time;
+
+	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
+	if (!time)
+		usb_kill_anchored_urbs(&dev->submitted);
+	usb_kill_urb(dev->bulk_in_urb);
+}
+
+static int skel_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct usb_skel *dev = usb_get_intfdata(intf);
+
+	if (!dev)
+		return 0;
+	skel_draw_down(dev);
+	return 0;
+}
+
+static int skel_resume(struct usb_interface *intf)
+{
+	return 0;
+}
+
+static int skel_pre_reset(struct usb_interface *intf)
+{
+	struct usb_skel *dev = usb_get_intfdata(intf);
+
+	mutex_lock(&dev->io_mutex);
+	skel_draw_down(dev);
+
+	return 0;
+}
+
+static int skel_post_reset(struct usb_interface *intf)
+{
+	struct usb_skel *dev = usb_get_intfdata(intf);
+
+	/* we are sure no URBs are active - no locking needed */
+	dev->errors = -EPIPE;
+	mutex_unlock(&dev->io_mutex);
+
+	return 0;
+}
+
+static struct usb_driver skel_driver = {
+	.name =		"skeleton",
+	.probe =	skel_probe,
+	.disconnect =	skel_disconnect,
+	.suspend =	skel_suspend,
+	.resume =	skel_resume,
+	.pre_reset =	skel_pre_reset,
+	.post_reset =	skel_post_reset,
+	.id_table =	skel_table,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(skel_driver);
+
+MODULE_LICENSE("GPL v2");