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, 605 insertions, 0 deletions

diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c
new file mode 100644
index 000000000..9c06f7775
--- /dev/null
+++ b/drivers/usb/misc/chaoskey.c
@@ -0,0 +1,605 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * chaoskey - driver for ChaosKey device from Altus Metrum.
+ *
+ * This device provides true random numbers using a noise source based
+ * on a reverse-biased p-n junction in avalanche breakdown. More
+ * details can be found at http://chaoskey.org
+ *
+ * The driver connects to the kernel hardware RNG interface to provide
+ * entropy for /dev/random and other kernel activities. It also offers
+ * a separate /dev/ entry to allow for direct access to the random
+ * bit stream.
+ *
+ * Copyright © 2015 Keith Packard <keithp@keithp.com>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/wait.h>
+#include <linux/hw_random.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+
+static struct usb_driver chaoskey_driver;
+static struct usb_class_driver chaoskey_class;
+static int chaoskey_rng_read(struct hwrng *rng, void *data,
+			     size_t max, bool wait);
+
+static DEFINE_MUTEX(chaoskey_list_lock);
+
+#define usb_dbg(usb_if, format, arg...) \
+	dev_dbg(&(usb_if)->dev, format, ## arg)
+
+#define usb_err(usb_if, format, arg...) \
+	dev_err(&(usb_if)->dev, format, ## arg)
+
+/* Version Information */
+#define DRIVER_AUTHOR	"Keith Packard, keithp@keithp.com"
+#define DRIVER_DESC	"Altus Metrum ChaosKey driver"
+#define DRIVER_SHORT	"chaoskey"
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+#define CHAOSKEY_VENDOR_ID	0x1d50	/* OpenMoko */
+#define CHAOSKEY_PRODUCT_ID	0x60c6	/* ChaosKey */
+
+#define ALEA_VENDOR_ID		0x12d8	/* Araneus */
+#define ALEA_PRODUCT_ID		0x0001	/* Alea I */
+
+#define CHAOSKEY_BUF_LEN	64	/* max size of USB full speed packet */
+
+#define NAK_TIMEOUT (HZ)		/* normal stall/wait timeout */
+#define ALEA_FIRST_TIMEOUT (HZ*3)	/* first stall/wait timeout for Alea */
+
+#ifdef CONFIG_USB_DYNAMIC_MINORS
+#define USB_CHAOSKEY_MINOR_BASE 0
+#else
+
+/* IOWARRIOR_MINOR_BASE + 16, not official yet */
+#define USB_CHAOSKEY_MINOR_BASE 224
+#endif
+
+static const struct usb_device_id chaoskey_table[] = {
+	{ USB_DEVICE(CHAOSKEY_VENDOR_ID, CHAOSKEY_PRODUCT_ID) },
+	{ USB_DEVICE(ALEA_VENDOR_ID, ALEA_PRODUCT_ID) },
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, chaoskey_table);
+
+static void chaos_read_callback(struct urb *urb);
+
+/* Driver-local specific stuff */
+struct chaoskey {
+	struct usb_interface *interface;
+	char in_ep;
+	struct mutex lock;
+	struct mutex rng_lock;
+	int open;			/* open count */
+	bool present;			/* device not disconnected */
+	bool reading;			/* ongoing IO */
+	bool reads_started;		/* track first read for Alea */
+	int size;			/* size of buf */
+	int valid;			/* bytes of buf read */
+	int used;			/* bytes of buf consumed */
+	char *name;			/* product + serial */
+	struct hwrng hwrng;		/* Embedded struct for hwrng */
+	int hwrng_registered;		/* registered with hwrng API */
+	wait_queue_head_t wait_q;	/* for timeouts */
+	struct urb *urb;		/* for performing IO */
+	char *buf;
+};
+
+static void chaoskey_free(struct chaoskey *dev)
+{
+	if (dev) {
+		usb_dbg(dev->interface, "free");
+		usb_free_urb(dev->urb);
+		kfree(dev->name);
+		kfree(dev->buf);
+		usb_put_intf(dev->interface);
+		kfree(dev);
+	}
+}
+
+static int chaoskey_probe(struct usb_interface *interface,
+			  const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(interface);
+	struct usb_host_interface *altsetting = interface->cur_altsetting;
+	struct usb_endpoint_descriptor *epd;
+	int in_ep;
+	struct chaoskey *dev;
+	int result = -ENOMEM;
+	int size;
+	int res;
+
+	usb_dbg(interface, "probe %s-%s", udev->product, udev->serial);
+
+	/* Find the first bulk IN endpoint and its packet size */
+	res = usb_find_bulk_in_endpoint(altsetting, &epd);
+	if (res) {
+		usb_dbg(interface, "no IN endpoint found");
+		return res;
+	}
+
+	in_ep = usb_endpoint_num(epd);
+	size = usb_endpoint_maxp(epd);
+
+	/* Validate endpoint and size */
+	if (size <= 0) {
+		usb_dbg(interface, "invalid size (%d)", size);
+		return -ENODEV;
+	}
+
+	if (size > CHAOSKEY_BUF_LEN) {
+		usb_dbg(interface, "size reduced from %d to %d\n",
+			size, CHAOSKEY_BUF_LEN);
+		size = CHAOSKEY_BUF_LEN;
+	}
+
+	/* Looks good, allocate and initialize */
+
+	dev = kzalloc_obj(struct chaoskey);
+
+	if (dev == NULL)
+		goto out;
+
+	dev->interface = usb_get_intf(interface);
+
+	dev->buf = kmalloc(size, GFP_KERNEL);
+
+	if (dev->buf == NULL)
+		goto out;
+
+	dev->urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!dev->urb)
+		goto out;
+
+	usb_fill_bulk_urb(dev->urb,
+		udev,
+		usb_rcvbulkpipe(udev, in_ep),
+		dev->buf,
+		size,
+		chaos_read_callback,
+		dev);
+
+	/* Construct a name using the product and serial values. Each
+	 * device needs a unique name for the hwrng code
+	 */
+
+	if (udev->product && udev->serial) {
+		dev->name = kasprintf(GFP_KERNEL, "%s-%s", udev->product,
+				      udev->serial);
+		if (dev->name == NULL)
+			goto out;
+	}
+
+	dev->in_ep = in_ep;
+
+	if (le16_to_cpu(udev->descriptor.idVendor) != ALEA_VENDOR_ID)
+		dev->reads_started = true;
+
+	dev->size = size;
+	dev->present = true;
+
+	init_waitqueue_head(&dev->wait_q);
+
+	mutex_init(&dev->lock);
+	mutex_init(&dev->rng_lock);
+
+	usb_set_intfdata(interface, dev);
+
+	result = usb_register_dev(interface, &chaoskey_class);
+	if (result) {
+		usb_err(interface, "Unable to allocate minor number.");
+		goto out;
+	}
+
+	dev->hwrng.name = dev->name ? dev->name : chaoskey_driver.name;
+	dev->hwrng.read = chaoskey_rng_read;
+
+	dev->hwrng_registered = (hwrng_register(&dev->hwrng) == 0);
+	if (!dev->hwrng_registered)
+		usb_err(interface, "Unable to register with hwrng");
+
+	usb_enable_autosuspend(udev);
+
+	usb_dbg(interface, "chaoskey probe success, size %d", dev->size);
+	return 0;
+
+out:
+	usb_set_intfdata(interface, NULL);
+	chaoskey_free(dev);
+	return result;
+}
+
+static void chaoskey_disconnect(struct usb_interface *interface)
+{
+	struct chaoskey	*dev;
+
+	usb_dbg(interface, "disconnect");
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		usb_dbg(interface, "disconnect failed - no dev");
+		return;
+	}
+
+	if (dev->hwrng_registered)
+		hwrng_unregister(&dev->hwrng);
+
+	usb_deregister_dev(interface, &chaoskey_class);
+
+	usb_set_intfdata(interface, NULL);
+	mutex_lock(&chaoskey_list_lock);
+	mutex_lock(&dev->lock);
+
+	dev->present = false;
+	usb_poison_urb(dev->urb);
+
+	if (!dev->open) {
+		mutex_unlock(&dev->lock);
+		chaoskey_free(dev);
+	} else
+		mutex_unlock(&dev->lock);
+
+	mutex_unlock(&chaoskey_list_lock);
+	usb_dbg(interface, "disconnect done");
+}
+
+static int chaoskey_open(struct inode *inode, struct file *file)
+{
+	struct chaoskey *dev;
+	struct usb_interface *interface;
+	int rv = 0;
+
+	/* get the interface from minor number and driver information */
+	interface = usb_find_interface(&chaoskey_driver, iminor(inode));
+	if (!interface)
+		return -ENODEV;
+
+	usb_dbg(interface, "open");
+
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		usb_dbg(interface, "open (dev)");
+		return -ENODEV;
+	}
+
+	file->private_data = dev;
+	mutex_lock(&chaoskey_list_lock);
+	mutex_lock(&dev->lock);
+	if (dev->present)
+		++dev->open;
+	else
+		rv = -ENODEV;
+	mutex_unlock(&dev->lock);
+	mutex_unlock(&chaoskey_list_lock);
+
+	return rv;
+}
+
+static int chaoskey_release(struct inode *inode, struct file *file)
+{
+	struct chaoskey *dev = file->private_data;
+	struct usb_interface *interface;
+	int rv = 0;
+
+	if (dev == NULL)
+		return -ENODEV;
+
+	interface = dev->interface;
+
+	usb_dbg(interface, "release");
+
+	mutex_lock(&chaoskey_list_lock);
+	mutex_lock(&dev->lock);
+
+	usb_dbg(interface, "open count at release is %d", dev->open);
+
+	if (dev->open <= 0) {
+		usb_dbg(interface, "invalid open count (%d)", dev->open);
+		rv = -ENODEV;
+		goto bail;
+	}
+
+	--dev->open;
+
+	if (!dev->present) {
+		if (dev->open == 0) {
+			mutex_unlock(&dev->lock);
+			chaoskey_free(dev);
+			goto destruction;
+		}
+	}
+bail:
+	mutex_unlock(&dev->lock);
+destruction:
+	mutex_unlock(&chaoskey_list_lock);
+	return rv;
+}
+
+static void chaos_read_callback(struct urb *urb)
+{
+	struct chaoskey *dev = urb->context;
+	int status = urb->status;
+
+	usb_dbg(dev->interface, "callback status (%d)", status);
+
+	if (status == 0)
+		dev->valid = urb->actual_length;
+	else
+		dev->valid = 0;
+
+	dev->used = 0;
+
+	/* must be seen first before validity is announced */
+	smp_wmb();
+
+	dev->reading = false;
+	wake_up(&dev->wait_q);
+}
+
+/* Fill the buffer. Called with dev->lock held
+ */
+static int _chaoskey_fill(struct chaoskey *dev)
+{
+	DEFINE_WAIT(wait);
+	int result;
+	bool started;
+
+	usb_dbg(dev->interface, "fill");
+
+	/* Return immediately if someone called before the buffer was
+	 * empty */
+	if (dev->valid != dev->used) {
+		usb_dbg(dev->interface, "not empty yet (valid %d used %d)",
+			dev->valid, dev->used);
+		return 0;
+	}
+
+	/* Bail if the device has been removed */
+	if (!dev->present) {
+		usb_dbg(dev->interface, "device not present");
+		return -ENODEV;
+	}
+
+	/* Make sure the device is awake */
+	result = usb_autopm_get_interface(dev->interface);
+	if (result) {
+		usb_dbg(dev->interface, "wakeup failed (result %d)", result);
+		return result;
+	}
+
+	dev->reading = true;
+	result = usb_submit_urb(dev->urb, GFP_KERNEL);
+	if (result < 0) {
+		result = usb_translate_errors(result);
+		dev->reading = false;
+		goto out;
+	}
+
+	/* The first read on the Alea takes a little under 2 seconds.
+	 * Reads after the first read take only a few microseconds
+	 * though.  Presumably the entropy-generating circuit needs
+	 * time to ramp up.  So, we wait longer on the first read.
+	 */
+	started = dev->reads_started;
+	dev->reads_started = true;
+	result = wait_event_interruptible_timeout(
+		dev->wait_q,
+		!dev->reading,
+		(started ? NAK_TIMEOUT : ALEA_FIRST_TIMEOUT) );
+
+	if (result < 0) {
+		usb_kill_urb(dev->urb);
+		goto out;
+	}
+
+	if (result == 0) {
+		result = -ETIMEDOUT;
+		usb_kill_urb(dev->urb);
+	} else {
+		result = dev->valid;
+	}
+out:
+	/* Let the device go back to sleep eventually */
+	usb_autopm_put_interface(dev->interface);
+
+	usb_dbg(dev->interface, "read %d bytes", dev->valid);
+
+	return result;
+}
+
+static ssize_t chaoskey_read(struct file *file,
+			     char __user *buffer,
+			     size_t count,
+			     loff_t *ppos)
+{
+	struct chaoskey *dev;
+	ssize_t read_count = 0;
+	int this_time;
+	int result = 0;
+	unsigned long remain;
+
+	dev = file->private_data;
+
+	if (dev == NULL || !dev->present)
+		return -ENODEV;
+
+	usb_dbg(dev->interface, "read %zu", count);
+
+	while (count > 0) {
+
+		/* Grab the rng_lock briefly to ensure that the hwrng interface
+		 * gets priority over other user access
+		 */
+		result = mutex_lock_interruptible(&dev->rng_lock);
+		if (result)
+			goto bail;
+		mutex_unlock(&dev->rng_lock);
+
+		if (file->f_flags & O_NONBLOCK) {
+			result = mutex_trylock(&dev->lock);
+			if (result == 0) {
+				result = -EAGAIN;
+				goto bail;
+			} else {
+				result = 0;
+			}
+		} else {
+			result = mutex_lock_interruptible(&dev->lock);
+			if (result)
+				goto bail;
+		}
+		if (dev->valid == dev->used) {
+			result = _chaoskey_fill(dev);
+			if (result < 0) {
+				mutex_unlock(&dev->lock);
+				goto bail;
+			}
+		}
+
+		this_time = dev->valid - dev->used;
+		if (this_time > count)
+			this_time = count;
+
+		remain = copy_to_user(buffer, dev->buf + dev->used, this_time);
+		if (remain) {
+			result = -EFAULT;
+
+			/* Consume the bytes that were copied so we don't leak
+			 * data to user space
+			 */
+			dev->used += this_time - remain;
+			mutex_unlock(&dev->lock);
+			goto bail;
+		}
+
+		count -= this_time;
+		read_count += this_time;
+		buffer += this_time;
+		dev->used += this_time;
+		mutex_unlock(&dev->lock);
+	}
+bail:
+	if (read_count) {
+		usb_dbg(dev->interface, "read %zu bytes", read_count);
+		return read_count;
+	}
+	usb_dbg(dev->interface, "empty read, result %d", result);
+	if (result == -ETIMEDOUT)
+		result = -EAGAIN;
+	return result;
+}
+
+static int chaoskey_rng_read(struct hwrng *rng, void *data,
+			     size_t max, bool wait)
+{
+	struct chaoskey *dev = container_of(rng, struct chaoskey, hwrng);
+	int this_time;
+
+	usb_dbg(dev->interface, "rng_read max %zu wait %d", max, wait);
+
+	if (!dev->present) {
+		usb_dbg(dev->interface, "device not present");
+		return 0;
+	}
+
+	/* Hold the rng_lock until we acquire the device lock so that
+	 * this operation gets priority over other user access to the
+	 * device
+	 */
+	mutex_lock(&dev->rng_lock);
+
+	mutex_lock(&dev->lock);
+
+	mutex_unlock(&dev->rng_lock);
+
+	/* Try to fill the buffer if empty. It doesn't actually matter
+	 * if _chaoskey_fill works; we'll just return zero bytes as
+	 * the buffer will still be empty
+	 */
+	if (dev->valid == dev->used)
+		(void) _chaoskey_fill(dev);
+
+	this_time = dev->valid - dev->used;
+	if (this_time > max)
+		this_time = max;
+
+	memcpy(data, dev->buf + dev->used, this_time);
+
+	dev->used += this_time;
+
+	mutex_unlock(&dev->lock);
+
+	usb_dbg(dev->interface, "rng_read this_time %d\n", this_time);
+	return this_time;
+}
+
+#ifdef CONFIG_PM
+static int chaoskey_suspend(struct usb_interface *interface,
+			    pm_message_t message)
+{
+	usb_dbg(interface, "suspend");
+	return 0;
+}
+
+static int chaoskey_resume(struct usb_interface *interface)
+{
+	struct chaoskey *dev;
+	struct usb_device *udev = interface_to_usbdev(interface);
+
+	usb_dbg(interface, "resume");
+	dev = usb_get_intfdata(interface);
+
+	/*
+	 * We may have lost power.
+	 * In that case the device that needs a long time
+	 * for the first requests needs an extended timeout
+	 * again
+	 */
+	if (le16_to_cpu(udev->descriptor.idVendor) == ALEA_VENDOR_ID)
+		dev->reads_started = false;
+
+	return 0;
+}
+#else
+#define chaoskey_suspend NULL
+#define chaoskey_resume NULL
+#endif
+
+/* file operation pointers */
+static const struct file_operations chaoskey_fops = {
+	.owner = THIS_MODULE,
+	.read = chaoskey_read,
+	.open = chaoskey_open,
+	.release = chaoskey_release,
+	.llseek = default_llseek,
+};
+
+/* class driver information */
+static struct usb_class_driver chaoskey_class = {
+	.name = "chaoskey%d",
+	.fops = &chaoskey_fops,
+	.minor_base = USB_CHAOSKEY_MINOR_BASE,
+};
+
+/* usb specific object needed to register this driver with the usb subsystem */
+static struct usb_driver chaoskey_driver = {
+	.name = DRIVER_SHORT,
+	.probe = chaoskey_probe,
+	.disconnect = chaoskey_disconnect,
+	.suspend = chaoskey_suspend,
+	.resume = chaoskey_resume,
+	.reset_resume = chaoskey_resume,
+	.id_table = chaoskey_table,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(chaoskey_driver);
+