From 963a14fb9c43f0a6b38fbe3da0b894a147c71388 Mon Sep 17 00:00:00 2001
From: Hillf Danton <hdanton@sina.com>
Date: Tue, 6 Aug 2019 16:40:15 +0800
Subject: [PATCH] HID: hiddev: do cleanup in failure of opening a device

commit 6d4472d7bec39917b54e4e80245784ea5d60ce49 upstream.

Undo what we did for opening before releasing the memory slice.

Reported-by: syzbot <syzbot+62a1e04fd3ec2abf099e@syzkaller.appspotmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/hid/usbhid/hiddev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 0bfc2009e407..8903ea09ac58 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -330,6 +330,10 @@ static int hiddev_open(struct inode *inode, struct file *file)
 	return 0;
 bail_unlock:
 	mutex_unlock(&hiddev->existancelock);
+
+	spin_lock_irq(&list->hiddev->list_lock);
+	list_del(&list->node);
+	spin_unlock_irq(&list->hiddev->list_lock);
 bail:
 	file->private_data = NULL;
 	vfree(list);