linux-kernel - [PATCH 5.10 015/142] media: rc: ensure that uevent can be read directly after rc device register

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Date:   Tue,  2 Feb 2021 14:36:18 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sean Young <sean@...s.org>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Subject: [PATCH 5.10 015/142] media: rc: ensure that uevent can be read directly after rc device register

From: Sean Young <sean@...s.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@...r.kernel.org
Fixes: a2e2d73fa281 ("media: rc: do not access device via sysfs after rc_unregister_device()")
Signed-off-by: Sean Young <sean@...s.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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
@@ -1928,6 +1928,8 @@ 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;
@@ -1937,8 +1939,6 @@ 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