[PATCH 4.19 06/37] media: rc: ensure that uevent can be read directly after rc device register

Greg Kroah-Hartman
2021-02-02T17:21:48Z

From: Sean Young <sean@mess.org>

commit 896111dc4bcf887b835b3ef54f48b450d4692a1d upstream.

There is a race condition where if the /sys/class/rc0/uevent file is read
before rc_dev->registered is set to true, -ENODEV will be returned.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1901089

Cc: stable@vger.kernel.org
Fixes: a2e2d73fa281 ("media: rc: do not access device via sysfs after rc_unregister_device()")
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/media/rc/rc-main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -1875,6 +1875,8 @@ int rc_register_device(struct rc_dev *de
goto out_raw;
}

+ dev->registered = true;
+
rc = device_add(&dev->dev);
if (rc)
goto out_rx_free;
@@ -1884,8 +1886,6 @@ int rc_register_device(struct rc_dev *de
dev->device_name ?: "Unspecified device", path ?: "N/A");
kfree(path);

- dev->registered = true;
-
/*
* once the the input device is registered in rc_setup_rx_device,
* userspace can open the input device and rc_open() will be called