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, 572 insertions, 0 deletions

diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
new file mode 100644
index 000000000..6471d836f
--- /dev/null
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -0,0 +1,572 @@
+/*
+ * Xen para-virtual input device
+ *
+ * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
+ * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
+ *
+ *  Based on linux/drivers/input/mouse/sermouse.c
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License. See the file COPYING in the main directory of this archive for
+ *  more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/slab.h>
+
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+#include <xen/interface/grant_table.h>
+#include <xen/interface/io/fbif.h>
+#include <xen/interface/io/kbdif.h>
+#include <xen/xenbus.h>
+#include <xen/platform_pci.h>
+
+struct xenkbd_info {
+	struct input_dev *kbd;
+	struct input_dev *ptr;
+	struct input_dev *mtouch;
+	struct xenkbd_page *page;
+	int gref;
+	int irq;
+	struct xenbus_device *xbdev;
+	char phys[32];
+	/* current MT slot/contact ID we are injecting events in */
+	int mtouch_cur_contact_id;
+};
+
+enum { KPARAM_X, KPARAM_Y, KPARAM_CNT };
+static int ptr_size[KPARAM_CNT] = { XENFB_WIDTH, XENFB_HEIGHT };
+module_param_array(ptr_size, int, NULL, 0444);
+MODULE_PARM_DESC(ptr_size,
+	"Pointing device width, height in pixels (default 800,600)");
+
+static void xenkbd_remove(struct xenbus_device *);
+static int xenkbd_connect_backend(struct xenbus_device *, struct xenkbd_info *);
+static void xenkbd_disconnect_backend(struct xenkbd_info *);
+
+/*
+ * Note: if you need to send out events, see xenfb_do_update() for how
+ * to do that.
+ */
+
+static void xenkbd_handle_motion_event(struct xenkbd_info *info,
+				       struct xenkbd_motion *motion)
+{
+	if (unlikely(!info->ptr))
+		return;
+
+	input_report_rel(info->ptr, REL_X, motion->rel_x);
+	input_report_rel(info->ptr, REL_Y, motion->rel_y);
+	if (motion->rel_z)
+		input_report_rel(info->ptr, REL_WHEEL, -motion->rel_z);
+	input_sync(info->ptr);
+}
+
+static void xenkbd_handle_position_event(struct xenkbd_info *info,
+					 struct xenkbd_position *pos)
+{
+	if (unlikely(!info->ptr))
+		return;
+
+	input_report_abs(info->ptr, ABS_X, pos->abs_x);
+	input_report_abs(info->ptr, ABS_Y, pos->abs_y);
+	if (pos->rel_z)
+		input_report_rel(info->ptr, REL_WHEEL, -pos->rel_z);
+	input_sync(info->ptr);
+}
+
+static void xenkbd_handle_key_event(struct xenkbd_info *info,
+				    struct xenkbd_key *key)
+{
+	struct input_dev *dev;
+	int value = key->pressed;
+
+	if (test_bit(key->keycode, info->ptr->keybit)) {
+		dev = info->ptr;
+	} else if (test_bit(key->keycode, info->kbd->keybit)) {
+		dev = info->kbd;
+		if (key->pressed && test_bit(key->keycode, info->kbd->key))
+			value = 2; /* Mark as autorepeat */
+	} else {
+		pr_warn("unhandled keycode 0x%x\n", key->keycode);
+		return;
+	}
+
+	if (unlikely(!dev))
+		return;
+
+	input_event(dev, EV_KEY, key->keycode, value);
+	input_sync(dev);
+}
+
+static void xenkbd_handle_mt_event(struct xenkbd_info *info,
+				   struct xenkbd_mtouch *mtouch)
+{
+	if (unlikely(!info->mtouch))
+		return;
+
+	if (mtouch->contact_id != info->mtouch_cur_contact_id) {
+		info->mtouch_cur_contact_id = mtouch->contact_id;
+		input_mt_slot(info->mtouch, mtouch->contact_id);
+	}
+
+	switch (mtouch->event_type) {
+	case XENKBD_MT_EV_DOWN:
+		input_mt_report_slot_state(info->mtouch, MT_TOOL_FINGER, true);
+		fallthrough;
+
+	case XENKBD_MT_EV_MOTION:
+		input_report_abs(info->mtouch, ABS_MT_POSITION_X,
+				 mtouch->u.pos.abs_x);
+		input_report_abs(info->mtouch, ABS_MT_POSITION_Y,
+				 mtouch->u.pos.abs_y);
+		break;
+
+	case XENKBD_MT_EV_SHAPE:
+		input_report_abs(info->mtouch, ABS_MT_TOUCH_MAJOR,
+				 mtouch->u.shape.major);
+		input_report_abs(info->mtouch, ABS_MT_TOUCH_MINOR,
+				 mtouch->u.shape.minor);
+		break;
+
+	case XENKBD_MT_EV_ORIENT:
+		input_report_abs(info->mtouch, ABS_MT_ORIENTATION,
+				 mtouch->u.orientation);
+		break;
+
+	case XENKBD_MT_EV_UP:
+		input_mt_report_slot_inactive(info->mtouch);
+		break;
+
+	case XENKBD_MT_EV_SYN:
+		input_mt_sync_frame(info->mtouch);
+		input_sync(info->mtouch);
+		break;
+	}
+}
+
+static void xenkbd_handle_event(struct xenkbd_info *info,
+				union xenkbd_in_event *event)
+{
+	switch (event->type) {
+	case XENKBD_TYPE_MOTION:
+		xenkbd_handle_motion_event(info, &event->motion);
+		break;
+
+	case XENKBD_TYPE_KEY:
+		xenkbd_handle_key_event(info, &event->key);
+		break;
+
+	case XENKBD_TYPE_POS:
+		xenkbd_handle_position_event(info, &event->pos);
+		break;
+
+	case XENKBD_TYPE_MTOUCH:
+		xenkbd_handle_mt_event(info, &event->mtouch);
+		break;
+	}
+}
+
+static irqreturn_t input_handler(int rq, void *dev_id)
+{
+	struct xenkbd_info *info = dev_id;
+	struct xenkbd_page *page = info->page;
+	__u32 cons, prod;
+
+	prod = page->in_prod;
+	if (prod == page->in_cons)
+		return IRQ_HANDLED;
+	rmb();			/* ensure we see ring contents up to prod */
+	for (cons = page->in_cons; cons != prod; cons++)
+		xenkbd_handle_event(info, &XENKBD_IN_RING_REF(page, cons));
+	mb();			/* ensure we got ring contents */
+	page->in_cons = cons;
+	notify_remote_via_irq(info->irq);
+
+	return IRQ_HANDLED;
+}
+
+static int xenkbd_probe(struct xenbus_device *dev,
+				  const struct xenbus_device_id *id)
+{
+	int ret, i;
+	bool with_mtouch, with_kbd, with_ptr;
+	struct xenkbd_info *info;
+	struct input_dev *kbd, *ptr, *mtouch;
+
+	info = kzalloc_obj(*info);
+	if (!info) {
+		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
+		return -ENOMEM;
+	}
+	dev_set_drvdata(&dev->dev, info);
+	info->xbdev = dev;
+	info->irq = -1;
+	info->gref = -1;
+	snprintf(info->phys, sizeof(info->phys), "xenbus/%s", dev->nodename);
+
+	info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	if (!info->page)
+		goto error_nomem;
+
+	/*
+	 * The below are reverse logic, e.g. if the feature is set, then
+	 * do not expose the corresponding virtual device.
+	 */
+	with_kbd = !xenbus_read_unsigned(dev->otherend,
+					 XENKBD_FIELD_FEAT_DSBL_KEYBRD, 0);
+
+	with_ptr = !xenbus_read_unsigned(dev->otherend,
+					 XENKBD_FIELD_FEAT_DSBL_POINTER, 0);
+
+	/* Direct logic: if set, then create multi-touch device. */
+	with_mtouch = xenbus_read_unsigned(dev->otherend,
+					   XENKBD_FIELD_FEAT_MTOUCH, 0);
+	if (with_mtouch) {
+		ret = xenbus_write(XBT_NIL, dev->nodename,
+				   XENKBD_FIELD_REQ_MTOUCH, "1");
+		if (ret) {
+			pr_warn("xenkbd: can't request multi-touch");
+			with_mtouch = 0;
+		}
+	}
+
+	/* keyboard */
+	if (with_kbd) {
+		kbd = input_allocate_device();
+		if (!kbd)
+			goto error_nomem;
+		kbd->name = "Xen Virtual Keyboard";
+		kbd->phys = info->phys;
+		kbd->id.bustype = BUS_PCI;
+		kbd->id.vendor = 0x5853;
+		kbd->id.product = 0xffff;
+
+		__set_bit(EV_KEY, kbd->evbit);
+		for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
+			__set_bit(i, kbd->keybit);
+		for (i = KEY_OK; i < KEY_MAX; i++)
+			__set_bit(i, kbd->keybit);
+
+		ret = input_register_device(kbd);
+		if (ret) {
+			input_free_device(kbd);
+			xenbus_dev_fatal(dev, ret,
+					 "input_register_device(kbd)");
+			goto error;
+		}
+		info->kbd = kbd;
+	}
+
+	/* pointing device */
+	if (with_ptr) {
+		unsigned int abs;
+
+		/* Set input abs params to match backend screen res */
+		abs = xenbus_read_unsigned(dev->otherend,
+					   XENKBD_FIELD_FEAT_ABS_POINTER, 0);
+		ptr_size[KPARAM_X] = xenbus_read_unsigned(dev->otherend,
+							  XENKBD_FIELD_WIDTH,
+							  ptr_size[KPARAM_X]);
+		ptr_size[KPARAM_Y] = xenbus_read_unsigned(dev->otherend,
+							  XENKBD_FIELD_HEIGHT,
+							  ptr_size[KPARAM_Y]);
+		if (abs) {
+			ret = xenbus_write(XBT_NIL, dev->nodename,
+					   XENKBD_FIELD_REQ_ABS_POINTER, "1");
+			if (ret) {
+				pr_warn("xenkbd: can't request abs-pointer\n");
+				abs = 0;
+			}
+		}
+
+		ptr = input_allocate_device();
+		if (!ptr)
+			goto error_nomem;
+		ptr->name = "Xen Virtual Pointer";
+		ptr->phys = info->phys;
+		ptr->id.bustype = BUS_PCI;
+		ptr->id.vendor = 0x5853;
+		ptr->id.product = 0xfffe;
+
+		if (abs) {
+			__set_bit(EV_ABS, ptr->evbit);
+			input_set_abs_params(ptr, ABS_X, 0,
+					     ptr_size[KPARAM_X], 0, 0);
+			input_set_abs_params(ptr, ABS_Y, 0,
+					     ptr_size[KPARAM_Y], 0, 0);
+		} else {
+			input_set_capability(ptr, EV_REL, REL_X);
+			input_set_capability(ptr, EV_REL, REL_Y);
+		}
+		input_set_capability(ptr, EV_REL, REL_WHEEL);
+
+		__set_bit(EV_KEY, ptr->evbit);
+		for (i = BTN_LEFT; i <= BTN_TASK; i++)
+			__set_bit(i, ptr->keybit);
+
+		ret = input_register_device(ptr);
+		if (ret) {
+			input_free_device(ptr);
+			xenbus_dev_fatal(dev, ret,
+					 "input_register_device(ptr)");
+			goto error;
+		}
+		info->ptr = ptr;
+	}
+
+	/* multi-touch device */
+	if (with_mtouch) {
+		int num_cont, width, height;
+
+		mtouch = input_allocate_device();
+		if (!mtouch)
+			goto error_nomem;
+
+		num_cont = xenbus_read_unsigned(info->xbdev->otherend,
+						XENKBD_FIELD_MT_NUM_CONTACTS,
+						1);
+		width = xenbus_read_unsigned(info->xbdev->otherend,
+					     XENKBD_FIELD_MT_WIDTH,
+					     XENFB_WIDTH);
+		height = xenbus_read_unsigned(info->xbdev->otherend,
+					      XENKBD_FIELD_MT_HEIGHT,
+					      XENFB_HEIGHT);
+
+		mtouch->name = "Xen Virtual Multi-touch";
+		mtouch->phys = info->phys;
+		mtouch->id.bustype = BUS_PCI;
+		mtouch->id.vendor = 0x5853;
+		mtouch->id.product = 0xfffd;
+
+		input_set_abs_params(mtouch, ABS_MT_TOUCH_MAJOR,
+				     0, 255, 0, 0);
+		input_set_abs_params(mtouch, ABS_MT_POSITION_X,
+				     0, width, 0, 0);
+		input_set_abs_params(mtouch, ABS_MT_POSITION_Y,
+				     0, height, 0, 0);
+
+		ret = input_mt_init_slots(mtouch, num_cont, INPUT_MT_DIRECT);
+		if (ret) {
+			input_free_device(mtouch);
+			xenbus_dev_fatal(info->xbdev, ret,
+					 "input_mt_init_slots");
+			goto error;
+		}
+
+		ret = input_register_device(mtouch);
+		if (ret) {
+			input_free_device(mtouch);
+			xenbus_dev_fatal(info->xbdev, ret,
+					 "input_register_device(mtouch)");
+			goto error;
+		}
+		info->mtouch_cur_contact_id = -1;
+		info->mtouch = mtouch;
+	}
+
+	if (!(with_kbd || with_ptr || with_mtouch)) {
+		ret = -ENXIO;
+		goto error;
+	}
+
+	ret = xenkbd_connect_backend(dev, info);
+	if (ret < 0)
+		goto error;
+
+	return 0;
+
+ error_nomem:
+	ret = -ENOMEM;
+	xenbus_dev_fatal(dev, ret, "allocating device memory");
+ error:
+	xenkbd_remove(dev);
+	return ret;
+}
+
+static int xenkbd_resume(struct xenbus_device *dev)
+{
+	struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
+
+	xenkbd_disconnect_backend(info);
+	memset(info->page, 0, PAGE_SIZE);
+	return xenkbd_connect_backend(dev, info);
+}
+
+static void xenkbd_remove(struct xenbus_device *dev)
+{
+	struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
+
+	xenkbd_disconnect_backend(info);
+	if (info->kbd)
+		input_unregister_device(info->kbd);
+	if (info->ptr)
+		input_unregister_device(info->ptr);
+	if (info->mtouch)
+		input_unregister_device(info->mtouch);
+	free_page((unsigned long)info->page);
+	kfree(info);
+}
+
+static int xenkbd_connect_backend(struct xenbus_device *dev,
+				  struct xenkbd_info *info)
+{
+	int ret, evtchn;
+	struct xenbus_transaction xbt;
+
+	ret = gnttab_grant_foreign_access(dev->otherend_id,
+	                                  virt_to_gfn(info->page), 0);
+	if (ret < 0)
+		return ret;
+	info->gref = ret;
+
+	ret = xenbus_alloc_evtchn(dev, &evtchn);
+	if (ret)
+		goto error_grant;
+	ret = bind_evtchn_to_irqhandler(evtchn, input_handler,
+					0, dev->devicetype, info);
+	if (ret < 0) {
+		xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
+		goto error_evtchan;
+	}
+	info->irq = ret;
+
+ again:
+	ret = xenbus_transaction_start(&xbt);
+	if (ret) {
+		xenbus_dev_fatal(dev, ret, "starting transaction");
+		goto error_irqh;
+	}
+	ret = xenbus_printf(xbt, dev->nodename, XENKBD_FIELD_RING_REF, "%lu",
+			    virt_to_gfn(info->page));
+	if (ret)
+		goto error_xenbus;
+	ret = xenbus_printf(xbt, dev->nodename, XENKBD_FIELD_RING_GREF,
+			    "%u", info->gref);
+	if (ret)
+		goto error_xenbus;
+	ret = xenbus_printf(xbt, dev->nodename, XENKBD_FIELD_EVT_CHANNEL, "%u",
+			    evtchn);
+	if (ret)
+		goto error_xenbus;
+	ret = xenbus_transaction_end(xbt, 0);
+	if (ret) {
+		if (ret == -EAGAIN)
+			goto again;
+		xenbus_dev_fatal(dev, ret, "completing transaction");
+		goto error_irqh;
+	}
+
+	xenbus_switch_state(dev, XenbusStateInitialised);
+	return 0;
+
+ error_xenbus:
+	xenbus_transaction_end(xbt, 1);
+	xenbus_dev_fatal(dev, ret, "writing xenstore");
+ error_irqh:
+	unbind_from_irqhandler(info->irq, info);
+	info->irq = -1;
+ error_evtchan:
+	xenbus_free_evtchn(dev, evtchn);
+ error_grant:
+	gnttab_end_foreign_access(info->gref, NULL);
+	info->gref = -1;
+	return ret;
+}
+
+static void xenkbd_disconnect_backend(struct xenkbd_info *info)
+{
+	if (info->irq >= 0)
+		unbind_from_irqhandler(info->irq, info);
+	info->irq = -1;
+	if (info->gref >= 0)
+		gnttab_end_foreign_access(info->gref, NULL);
+	info->gref = -1;
+}
+
+static void xenkbd_backend_changed(struct xenbus_device *dev,
+				   enum xenbus_state backend_state)
+{
+	switch (backend_state) {
+	case XenbusStateInitialising:
+	case XenbusStateInitialised:
+	case XenbusStateReconfiguring:
+	case XenbusStateReconfigured:
+	case XenbusStateUnknown:
+		break;
+
+	case XenbusStateInitWait:
+		xenbus_switch_state(dev, XenbusStateConnected);
+		break;
+
+	case XenbusStateConnected:
+		/*
+		 * Work around xenbus race condition: If backend goes
+		 * through InitWait to Connected fast enough, we can
+		 * get Connected twice here.
+		 */
+		if (dev->state != XenbusStateConnected)
+			xenbus_switch_state(dev, XenbusStateConnected);
+		break;
+
+	case XenbusStateClosed:
+		if (dev->state == XenbusStateClosed)
+			break;
+		fallthrough;	/* Missed the backend's CLOSING state */
+	case XenbusStateClosing:
+		xenbus_frontend_closed(dev);
+		break;
+	}
+}
+
+static const struct xenbus_device_id xenkbd_ids[] = {
+	{ XENKBD_DRIVER_NAME },
+	{ "" }
+};
+
+static struct xenbus_driver xenkbd_driver = {
+	.ids = xenkbd_ids,
+	.probe = xenkbd_probe,
+	.remove = xenkbd_remove,
+	.resume = xenkbd_resume,
+	.otherend_changed = xenkbd_backend_changed,
+	.not_essential = true,
+};
+
+static int __init xenkbd_init(void)
+{
+	if (!xen_domain())
+		return -ENODEV;
+
+	/* Nothing to do if running in dom0. */
+	if (xen_initial_domain())
+		return -ENODEV;
+
+	if (!xen_has_pv_devices())
+		return -ENODEV;
+
+	return xenbus_register_frontend(&xenkbd_driver);
+}
+
+static void __exit xenkbd_cleanup(void)
+{
+	xenbus_unregister_driver(&xenkbd_driver);
+}
+
+module_init(xenkbd_init);
+module_exit(xenkbd_cleanup);
+
+MODULE_DESCRIPTION("Xen virtual keyboard/pointer device frontend");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("xen:" XENKBD_DRIVER_NAME);