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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot <syzbot+62a1e04fd3ec2abf099e@syzkaller.appspotmail.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Hillf Danton <hdanton@sina.com>, Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH 4.9 064/103] HID: hiddev: do cleanup in failure of opening a device
Date:   Thu, 22 Aug 2019 10:18:52 -0700
Message-Id: <20190822171731.370428664@linuxfoundation.org>
In-Reply-To: <20190822171728.445189830@linuxfoundation.org>
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From: Hillf Danton <hdanton@sina.com>

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(+)

--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -330,6 +330,10 @@ static int hiddev_open(struct inode *ino
 	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);