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, 523 insertions, 0 deletions

diff --git a/Documentation/usb/gadget_printer.rst b/Documentation/usb/gadget_printer.rst
new file mode 100644
index 000000000..e611a6d91
--- /dev/null
+++ b/Documentation/usb/gadget_printer.rst
@@ -0,0 +1,523 @@
+===============================
+Linux USB Printer Gadget Driver
+===============================
+
+06/04/2007
+
+Copyright (C) 2007 Craig W. Nadler <craig@nadler.us>
+
+
+
+General
+=======
+
+This driver may be used if you are writing printer firmware using Linux as
+the embedded OS. This driver has nothing to do with using a printer with
+your Linux host system.
+
+You will need a USB device controller and a Linux driver for it that accepts
+a gadget / "device class" driver using the Linux USB Gadget API. After the
+USB device controller driver is loaded then load the printer gadget driver.
+This will present a printer interface to the USB Host that your USB Device
+port is connected to.
+
+This driver is structured for printer firmware that runs in user mode. The
+user mode printer firmware will read and write data from the kernel mode
+printer gadget driver using a device file. The printer returns a printer status
+byte when the USB HOST sends a device request to get the printer status.  The
+user space firmware can read or write this status byte using a device file
+/dev/g_printer . Both blocking and non-blocking read/write calls are supported.
+
+
+
+
+Howto Use This Driver
+=====================
+
+To load the USB device controller driver and the printer gadget driver. The
+following example uses the Netchip 2280 USB device controller driver::
+
+	modprobe net2280
+	modprobe g_printer
+
+
+The follow command line parameter can be used when loading the printer gadget
+(ex: modprobe g_printer idVendor=0x0525 idProduct=0xa4a8 ):
+
+idVendor
+	This is the Vendor ID used in the device descriptor. The default is
+	the Netchip vendor id 0x0525. YOU MUST CHANGE TO YOUR OWN VENDOR ID
+	BEFORE RELEASING A PRODUCT. If you plan to release a product and don't
+	already have a Vendor ID please see www.usb.org for details on how to
+	get one.
+
+idProduct
+	This is the Product ID used in the device descriptor. The default
+	is 0xa4a8, you should change this to an ID that's not used by any of
+	your other USB products if you have any. It would be a good idea to
+	start numbering your products starting with say 0x0001.
+
+bcdDevice
+	This is the version number of your product. It would be a good idea
+	to put your firmware version here.
+
+iManufacturer
+	A string containing the name of the Vendor.
+
+iProduct
+	A string containing the Product Name.
+
+iSerialNum
+	A string containing the Serial Number. This should be changed for
+	each unit of your product.
+
+iPNPstring
+	The PNP ID string used for this printer. You will want to set
+	either on the command line or hard code the PNP ID string used for
+	your printer product.
+
+qlen
+	The number of 8k buffers to use per endpoint. The default is 10, you
+	should tune this for your product. You may also want to tune the
+	size of each buffer for your product.
+
+
+
+
+Using The Example Code
+======================
+
+This example code talks to stdout, instead of a print engine.
+
+To compile the test code below:
+
+1) save it to a file called prn_example.c
+2) compile the code with the follow command::
+
+	 gcc prn_example.c -o prn_example
+
+
+
+To read printer data from the host to stdout::
+
+	# prn_example -read_data
+
+
+To write printer data from a file (data_file) to the host::
+
+	# cat data_file | prn_example -write_data
+
+
+To get the current printer status for the gadget driver:::
+
+	# prn_example -get_status
+
+	Printer status is:
+	     Printer is NOT Selected
+	     Paper is Out
+	     Printer OK
+
+
+To set printer to Selected/On-line::
+
+	# prn_example -selected
+
+
+To set printer to Not Selected/Off-line::
+
+	# prn_example -not_selected
+
+
+To set paper status to paper out::
+
+	# prn_example -paper_out
+
+
+To set paper status to paper loaded::
+
+	# prn_example -paper_loaded
+
+
+To set error status to printer OK::
+
+	# prn_example -no_error
+
+
+To set error status to ERROR::
+
+	# prn_example -error
+
+
+
+
+Example Code
+============
+
+::
+
+
+  #include <stdio.h>
+  #include <stdlib.h>
+  #include <fcntl.h>
+  #include <linux/poll.h>
+  #include <sys/ioctl.h>
+  #include <linux/usb/g_printer.h>
+
+  #define PRINTER_FILE			"/dev/g_printer"
+  #define BUF_SIZE			512
+
+
+  /*
+   * 'usage()' - Show program usage.
+   */
+
+  static void
+  usage(const char *option)		/* I - Option string or NULL */
+  {
+	if (option) {
+		fprintf(stderr,"prn_example: Unknown option \"%s\"!\n",
+				option);
+	}
+
+	fputs("\n", stderr);
+	fputs("Usage: prn_example -[options]\n", stderr);
+	fputs("Options:\n", stderr);
+	fputs("\n", stderr);
+	fputs("-get_status    Get the current printer status.\n", stderr);
+	fputs("-selected      Set the selected status to selected.\n", stderr);
+	fputs("-not_selected  Set the selected status to NOT selected.\n",
+			stderr);
+	fputs("-error         Set the error status to error.\n", stderr);
+	fputs("-no_error      Set the error status to NO error.\n", stderr);
+	fputs("-paper_out     Set the paper status to paper out.\n", stderr);
+	fputs("-paper_loaded  Set the paper status to paper loaded.\n",
+			stderr);
+	fputs("-read_data     Read printer data from driver.\n", stderr);
+	fputs("-write_data    Write printer sata to driver.\n", stderr);
+	fputs("-NB_read_data  (Non-Blocking) Read printer data from driver.\n",
+			stderr);
+	fputs("\n\n", stderr);
+
+	exit(1);
+  }
+
+
+  static int
+  read_printer_data()
+  {
+	struct pollfd	fd[1];
+
+	/* Open device file for printer gadget. */
+	fd[0].fd = open(PRINTER_FILE, O_RDWR);
+	if (fd[0].fd < 0) {
+		printf("Error %d opening %s\n", fd[0].fd, PRINTER_FILE);
+		close(fd[0].fd);
+		return(-1);
+	}
+
+	fd[0].events = POLLIN | POLLRDNORM;
+
+	while (1) {
+		static char buf[BUF_SIZE];
+		int bytes_read;
+		int retval;
+
+		/* Wait for up to 1 second for data. */
+		retval = poll(fd, 1, 1000);
+
+		if (retval && (fd[0].revents & POLLRDNORM)) {
+
+			/* Read data from printer gadget driver. */
+			bytes_read = read(fd[0].fd, buf, BUF_SIZE);
+
+			if (bytes_read < 0) {
+				printf("Error %d reading from %s\n",
+						fd[0].fd, PRINTER_FILE);
+				close(fd[0].fd);
+				return(-1);
+			} else if (bytes_read > 0) {
+				/* Write data to standard OUTPUT (stdout). */
+				fwrite(buf, 1, bytes_read, stdout);
+				fflush(stdout);
+			}
+
+		}
+
+	}
+
+	/* Close the device file. */
+	close(fd[0].fd);
+
+	return 0;
+  }
+
+
+  static int
+  write_printer_data()
+  {
+	struct pollfd	fd[1];
+
+	/* Open device file for printer gadget. */
+	fd[0].fd = open (PRINTER_FILE, O_RDWR);
+	if (fd[0].fd < 0) {
+		printf("Error %d opening %s\n", fd[0].fd, PRINTER_FILE);
+		close(fd[0].fd);
+		return(-1);
+	}
+
+	fd[0].events = POLLOUT | POLLWRNORM;
+
+	while (1) {
+		int retval;
+		static char buf[BUF_SIZE];
+		/* Read data from standard INPUT (stdin). */
+		int bytes_read = fread(buf, 1, BUF_SIZE, stdin);
+
+		if (!bytes_read) {
+			break;
+		}
+
+		while (bytes_read) {
+
+			/* Wait for up to 1 second to sent data. */
+			retval = poll(fd, 1, 1000);
+
+			/* Write data to printer gadget driver. */
+			if (retval && (fd[0].revents & POLLWRNORM)) {
+				retval = write(fd[0].fd, buf, bytes_read);
+				if (retval < 0) {
+					printf("Error %d writing to %s\n",
+							fd[0].fd,
+							PRINTER_FILE);
+					close(fd[0].fd);
+					return(-1);
+				} else {
+					bytes_read -= retval;
+				}
+
+			}
+
+		}
+
+	}
+
+	/* Wait until the data has been sent. */
+	fsync(fd[0].fd);
+
+	/* Close the device file. */
+	close(fd[0].fd);
+
+	return 0;
+  }
+
+
+  static int
+  read_NB_printer_data()
+  {
+	int		fd;
+	static char	buf[BUF_SIZE];
+	int		bytes_read;
+
+	/* Open device file for printer gadget. */
+	fd = open(PRINTER_FILE, O_RDWR|O_NONBLOCK);
+	if (fd < 0) {
+		printf("Error %d opening %s\n", fd, PRINTER_FILE);
+		close(fd);
+		return(-1);
+	}
+
+	while (1) {
+		/* Read data from printer gadget driver. */
+		bytes_read = read(fd, buf, BUF_SIZE);
+		if (bytes_read <= 0) {
+			break;
+		}
+
+		/* Write data to standard OUTPUT (stdout). */
+		fwrite(buf, 1, bytes_read, stdout);
+		fflush(stdout);
+	}
+
+	/* Close the device file. */
+	close(fd);
+
+	return 0;
+  }
+
+
+  static int
+  get_printer_status()
+  {
+	int	retval;
+	int	fd;
+
+	/* Open device file for printer gadget. */
+	fd = open(PRINTER_FILE, O_RDWR);
+	if (fd < 0) {
+		printf("Error %d opening %s\n", fd, PRINTER_FILE);
+		close(fd);
+		return(-1);
+	}
+
+	/* Make the IOCTL call. */
+	retval = ioctl(fd, GADGET_GET_PRINTER_STATUS);
+	if (retval < 0) {
+		fprintf(stderr, "ERROR: Failed to set printer status\n");
+		return(-1);
+	}
+
+	/* Close the device file. */
+	close(fd);
+
+	return(retval);
+  }
+
+
+  static int
+  set_printer_status(unsigned char buf, int clear_printer_status_bit)
+  {
+	int	retval;
+	int	fd;
+
+	retval = get_printer_status();
+	if (retval < 0) {
+		fprintf(stderr, "ERROR: Failed to get printer status\n");
+		return(-1);
+	}
+
+	/* Open device file for printer gadget. */
+	fd = open(PRINTER_FILE, O_RDWR);
+
+	if (fd < 0) {
+		printf("Error %d opening %s\n", fd, PRINTER_FILE);
+		close(fd);
+		return(-1);
+	}
+
+	if (clear_printer_status_bit) {
+		retval &= ~buf;
+	} else {
+		retval |= buf;
+	}
+
+	/* Make the IOCTL call. */
+	if (ioctl(fd, GADGET_SET_PRINTER_STATUS, (unsigned char)retval)) {
+		fprintf(stderr, "ERROR: Failed to set printer status\n");
+		return(-1);
+	}
+
+	/* Close the device file. */
+	close(fd);
+
+	return 0;
+  }
+
+
+  static int
+  display_printer_status()
+  {
+	char	printer_status;
+
+	printer_status = get_printer_status();
+	if (printer_status < 0) {
+		fprintf(stderr, "ERROR: Failed to get printer status\n");
+		return(-1);
+	}
+
+	printf("Printer status is:\n");
+	if (printer_status & PRINTER_SELECTED) {
+		printf("     Printer is Selected\n");
+	} else {
+		printf("     Printer is NOT Selected\n");
+	}
+	if (printer_status & PRINTER_PAPER_EMPTY) {
+		printf("     Paper is Out\n");
+	} else {
+		printf("     Paper is Loaded\n");
+	}
+	if (printer_status & PRINTER_NOT_ERROR) {
+		printf("     Printer OK\n");
+	} else {
+		printf("     Printer ERROR\n");
+	}
+
+	return(0);
+  }
+
+
+  int
+  main(int  argc, char *argv[])
+  {
+	int	i;		/* Looping var */
+	int	retval = 0;
+
+	/* No Args */
+	if (argc == 1) {
+		usage(0);
+		exit(0);
+	}
+
+	for (i = 1; i < argc && !retval; i ++) {
+
+		if (argv[i][0] != '-') {
+			continue;
+		}
+
+		if (!strcmp(argv[i], "-get_status")) {
+			if (display_printer_status()) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-paper_loaded")) {
+			if (set_printer_status(PRINTER_PAPER_EMPTY, 1)) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-paper_out")) {
+			if (set_printer_status(PRINTER_PAPER_EMPTY, 0)) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-selected")) {
+			if (set_printer_status(PRINTER_SELECTED, 0)) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-not_selected")) {
+			if (set_printer_status(PRINTER_SELECTED, 1)) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-error")) {
+			if (set_printer_status(PRINTER_NOT_ERROR, 1)) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-no_error")) {
+			if (set_printer_status(PRINTER_NOT_ERROR, 0)) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-read_data")) {
+			if (read_printer_data()) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-write_data")) {
+			if (write_printer_data()) {
+				retval = 1;
+			}
+
+		} else if (!strcmp(argv[i], "-NB_read_data")) {
+			if (read_NB_printer_data()) {
+				retval = 1;
+			}
+
+		} else {
+			usage(argv[i]);
+			retval = 1;
+		}
+	}
+
+	exit(retval);
+  }