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, 304 insertions, 0 deletions

diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
new file mode 100644
index 000000000..29f091908
--- /dev/null
+++ b/drivers/usb/serial/console.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Serial Console driver
+ *
+ * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ * Thanks to Randy Dunlap for the original version of this code.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/console.h>
+#include <linux/serial.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+struct usbcons_info {
+	int			magic;
+	int			break_flag;
+	struct usb_serial_port	*port;
+};
+
+static struct usbcons_info usbcons_info;
+static struct console usbcons;
+
+/*
+ * ------------------------------------------------------------
+ * USB Serial console driver
+ *
+ * Much of the code here is copied from drivers/char/serial.c
+ * and implements a phony serial console in the same way that
+ * serial.c does so that in case some software queries it,
+ * it will get the same results.
+ *
+ * Things that are different from the way the serial port code
+ * does things, is that we call the lower level usb-serial
+ * driver code to initialize the device, and we set the initial
+ * console speeds based on the command line arguments.
+ * ------------------------------------------------------------
+ */
+
+static const struct tty_operations usb_console_fake_tty_ops = {
+};
+
+/*
+ * The parsing of the command line works exactly like the
+ * serial.c code, except that the specifier is "ttyUSB" instead
+ * of "ttyS".
+ */
+static int usb_console_setup(struct console *co, char *options)
+{
+	struct usbcons_info *info = &usbcons_info;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int doflow = 0;
+	int cflag = CREAD | HUPCL | CLOCAL;
+	char *s;
+	struct usb_serial *serial;
+	struct usb_serial_port *port;
+	int retval;
+	struct tty_struct *tty = NULL;
+	struct ktermios dummy;
+
+	if (options) {
+		baud = simple_strtoul(options, NULL, 10);
+		s = options;
+		while (*s >= '0' && *s <= '9')
+			s++;
+		if (*s)
+			parity = *s++;
+		if (*s)
+			bits   = *s++ - '0';
+		if (*s)
+			doflow = (*s++ == 'r');
+	}
+
+	/* Sane default */
+	if (baud == 0)
+		baud = 9600;
+
+	switch (bits) {
+	case 7:
+		cflag |= CS7;
+		break;
+	default:
+	case 8:
+		cflag |= CS8;
+		break;
+	}
+	switch (parity) {
+	case 'o': case 'O':
+		cflag |= PARODD;
+		break;
+	case 'e': case 'E':
+		cflag |= PARENB;
+		break;
+	}
+
+	if (doflow)
+		cflag |= CRTSCTS;
+
+	/*
+	 * no need to check the index here: if the index is wrong, console
+	 * code won't call us
+	 */
+	port = usb_serial_port_get_by_minor(co->index);
+	if (port == NULL) {
+		/* no device is connected yet, sorry :( */
+		pr_err("No USB device connected to ttyUSB%i\n", co->index);
+		return -ENODEV;
+	}
+	serial = port->serial;
+
+	retval = usb_autopm_get_interface(serial->interface);
+	if (retval)
+		goto error_get_interface;
+
+	tty_port_tty_set(&port->port, NULL);
+
+	info->port = port;
+
+	++port->port.count;
+	if (!tty_port_initialized(&port->port)) {
+		if (serial->type->set_termios) {
+			/*
+			 * allocate a fake tty so the driver can initialize
+			 * the termios structure, then later call set_termios to
+			 * configure according to command line arguments
+			 */
+			tty = kzalloc_obj(*tty);
+			if (!tty) {
+				retval = -ENOMEM;
+				goto reset_open_count;
+			}
+			kref_init(&tty->kref);
+			tty->driver = usb_serial_tty_driver;
+			tty->index = co->index;
+			init_ldsem(&tty->ldisc_sem);
+			spin_lock_init(&tty->files_lock);
+			INIT_LIST_HEAD(&tty->tty_files);
+			kref_get(&tty->driver->kref);
+			__module_get(tty->driver->owner);
+			tty->ops = &usb_console_fake_tty_ops;
+			tty_init_termios(tty);
+			tty_port_tty_set(&port->port, tty);
+		}
+
+		/* only call the device specific open if this
+		 * is the first time the port is opened */
+		retval = serial->type->open(NULL, port);
+		if (retval) {
+			dev_err(&port->dev, "could not open USB console port\n");
+			goto fail;
+		}
+
+		if (serial->type->set_termios) {
+			tty->termios.c_cflag = cflag;
+			tty_termios_encode_baud_rate(&tty->termios, baud, baud);
+			memset(&dummy, 0, sizeof(struct ktermios));
+			serial->type->set_termios(tty, port, &dummy);
+
+			tty_port_tty_set(&port->port, NULL);
+			tty_save_termios(tty);
+			tty_kref_put(tty);
+		}
+		tty_port_set_initialized(&port->port, true);
+	}
+	/* Now that any required fake tty operations are completed restore
+	 * the tty port count */
+	--port->port.count;
+	/* The console is special in terms of closing the device so
+	 * indicate this port is now acting as a system console. */
+	port->port.console = 1;
+
+	mutex_unlock(&serial->disc_mutex);
+	return retval;
+
+ fail:
+	tty_port_tty_set(&port->port, NULL);
+	tty_kref_put(tty);
+ reset_open_count:
+	port->port.count = 0;
+	info->port = NULL;
+	usb_autopm_put_interface(serial->interface);
+ error_get_interface:
+	mutex_unlock(&serial->disc_mutex);
+	usb_serial_put(serial);
+	return retval;
+}
+
+static void usb_console_write(struct console *co,
+					const char *buf, unsigned count)
+{
+	static struct usbcons_info *info = &usbcons_info;
+	struct usb_serial_port *port = info->port;
+	struct usb_serial *serial;
+	int retval = -ENODEV;
+
+	if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
+		return;
+	serial = port->serial;
+
+	if (count == 0)
+		return;
+
+	dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
+
+	if (!port->port.console) {
+		dev_dbg(&port->dev, "%s - port not opened\n", __func__);
+		return;
+	}
+
+	while (count) {
+		unsigned int i;
+		unsigned int lf;
+		/* search for LF so we can insert CR if necessary */
+		for (i = 0, lf = 0 ; i < count ; i++) {
+			if (*(buf + i) == 10) {
+				lf = 1;
+				i++;
+				break;
+			}
+		}
+		/* pass on to the driver specific version of this function if
+		   it is available */
+		retval = serial->type->write(NULL, port, buf, i);
+		dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
+		if (lf) {
+			/* append CR after LF */
+			unsigned char cr = 13;
+			retval = serial->type->write(NULL, port, &cr, 1);
+			dev_dbg(&port->dev, "%s - write cr: %d\n",
+							__func__, retval);
+		}
+		buf += i;
+		count -= i;
+	}
+}
+
+static struct tty_driver *usb_console_device(struct console *co, int *index)
+{
+	struct tty_driver **p = (struct tty_driver **)co->data;
+
+	if (!*p)
+		return NULL;
+
+	*index = co->index;
+	return *p;
+}
+
+static struct console usbcons = {
+	.name =		"ttyUSB",
+	.write =	usb_console_write,
+	.device =	usb_console_device,
+	.setup =	usb_console_setup,
+	.flags =	CON_PRINTBUFFER,
+	.index =	-1,
+	.data = 	&usb_serial_tty_driver,
+};
+
+void usb_serial_console_disconnect(struct usb_serial *serial)
+{
+	if (serial->port[0] && serial->port[0] == usbcons_info.port) {
+		usb_serial_console_exit();
+		usb_serial_put(serial);
+	}
+}
+
+void usb_serial_console_init(int minor)
+{
+	if (minor == 0) {
+		/*
+		 * Call register_console() if this is the first device plugged
+		 * in.  If we call it earlier, then the callback to
+		 * console_setup() will fail, as there is not a device seen by
+		 * the USB subsystem yet.
+		 */
+		/*
+		 * Register console.
+		 * NOTES:
+		 * console_setup() is called (back) immediately (from
+		 * register_console). console_write() is called immediately
+		 * from register_console iff CON_PRINTBUFFER is set in flags.
+		 */
+		pr_debug("registering the USB serial console.\n");
+		register_console(&usbcons);
+	}
+}
+
+void usb_serial_console_exit(void)
+{
+	if (usbcons_info.port) {
+		unregister_console(&usbcons);
+		usbcons_info.port->port.console = 0;
+		usbcons_info.port = NULL;
+	}
+}
+