[PATCH] HID: synchronize input before cleaning up a failed probe

[Yousef Alhouseen <alhouseenyousef@gmail.com>]

hid_device_io_start() allows reports to run concurrently with probe. If
the probe subsequently fails, __hid_device_probe() releases driver
resources and clears hdev->driver without first excluding those report
callbacks.

For example, a report may enter hidraw_report_event() while the failure
path frees the associated hidraw object, leading to a use-after-free when
the report takes the object's list lock.

Stop input before performing failed-probe cleanup. This reacquires
driver_input_lock and waits for any report callback already in progress.

Fixes: c849a6143bec ("HID: Separate struct hid_device's driver_lock into two locks.")
Reported-by: syzbot+9eebf5f6544c5e873858@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9eebf5f6544c5e873858
Signed-off-by: Yousef Alhouseen <alhouseenyousef@gmail.com>
---
 drivers/hid/hid-core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 41a79e43c82b..469b849b7a2a 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2835,6 +2835,8 @@ static int __hid_device_probe(struct hid_device *hdev, struct hid_driver *hdrv)
 	 */
 
 	if (ret) {
+		if (hdev->io_started)
+			hid_device_io_stop(hdev);
 		devres_release_group(&hdev->dev, hdev->devres_group_id);
 		hid_close_report(hdev);
 		hdev->driver = NULL;
-- 
2.54.0