1 files changed, 28 insertions, 7 deletions

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index e589060db280..d32fa4b508fc 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -25,8 +25,10 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/fs.h>
+#include <linux/lockdep.h>
 #include <linux/miscdevice.h>
 #include <linux/overflow.h>
+#include <linux/spinlock.h>
 #include <linux/input/mt.h>
 #include "../input-compat.h"
 
@@ -57,6 +59,7 @@ struct uinput_device {
 	struct input_dev	*dev;
 	struct mutex		mutex;
 	enum uinput_state	state;
+	spinlock_t		state_lock;
 	wait_queue_head_t	waitq;
 	unsigned char		ready;
 	unsigned char		head;
@@ -75,6 +78,8 @@ static int uinput_dev_event(struct input_dev *dev,
 	struct uinput_device	*udev = input_get_drvdata(dev);
 	struct timespec64	ts;
 
+	lockdep_assert_held(&dev->event_lock);
+
 	ktime_get_ts64(&ts);
 
 	udev->buff[udev->head] = (struct input_event) {
@@ -146,27 +151,26 @@ static void uinput_request_release_slot(struct uinput_device *udev,
 static int uinput_request_send(struct uinput_device *udev,
 			       struct uinput_request *request)
 {
-	int retval;
+	unsigned long flags;
+	int retval = 0;
 
-	retval = mutex_lock_interruptible(&udev->mutex);
-	if (retval)
-		return retval;
+	spin_lock(&udev->state_lock);
 
 	if (udev->state != UIST_CREATED) {
 		retval = -ENODEV;
 		goto out;
 	}
 
-	init_completion(&request->done);
-
 	/*
 	 * Tell our userspace application about this new request
 	 * by queueing an input event.
 	 */
+	spin_lock_irqsave(&udev->dev->event_lock, flags);
 	uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);
+	spin_unlock_irqrestore(&udev->dev->event_lock, flags);
 
  out:
-	mutex_unlock(&udev->mutex);
+	spin_unlock(&udev->state_lock);
 	return retval;
 }
 
@@ -175,6 +179,13 @@ static int uinput_request_submit(struct uinput_device *udev,
 {
 	int retval;
 
+	/*
+	 * Initialize completion before allocating the request slot.
+	 * Once the slot is allocated, uinput_flush_requests() may
+	 * complete it at any time, so it must be initialized first.
+	 */
+	init_completion(&request->done);
+
 	retval = uinput_request_reserve_slot(udev, request);
 	if (retval)
 		return retval;
@@ -289,7 +300,14 @@ static void uinput_destroy_device(struct uinput_device *udev)
 	struct input_dev *dev = udev->dev;
 	enum uinput_state old_state = udev->state;
 
+	/*
+	 * Update state under state_lock so that concurrent
+	 * uinput_request_send() sees the state change before we
+	 * flush pending requests and tear down the device.
+	 */
+	spin_lock(&udev->state_lock);
 	udev->state = UIST_NEW_DEVICE;
+	spin_unlock(&udev->state_lock);
 
 	if (dev) {
 		name = dev->name;
@@ -366,7 +384,9 @@ static int uinput_create_device(struct uinput_device *udev)
 	if (error)
 		goto fail2;
 
+	spin_lock(&udev->state_lock);
 	udev->state = UIST_CREATED;
+	spin_unlock(&udev->state_lock);
 
 	return 0;
 
@@ -384,6 +404,7 @@ static int uinput_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 
 	mutex_init(&newdev->mutex);
+	spin_lock_init(&newdev->state_lock);
 	spin_lock_init(&newdev->requests_lock);
 	init_waitqueue_head(&newdev->requests_waitq);
 	init_waitqueue_head(&newdev->waitq);