[lvc-project] [PATCH v4 3/4] HID: roccat: fix device access in roccat_release()

[Dmitry Antipov]

In roccat_release(), access the device using file-specific
reader data rather than global array, thus preventing the
case when original device was disconnected and a new device
has connected using the same slot indexed by minor number.

Reported-by: Sashiko <sashiko-bot at kernel.org>
Link: https://sashiko.dev/#/patchset/20260902094551.200587-1-dmantipov@yandex.ru?part=2
Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
v3 and upwards: unchanged
v2: initial version to join the series
---
 drivers/hid/hid-roccat.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/hid/hid-roccat.c b/drivers/hid/hid-roccat.c
index eb6b71417175..7890bf079a3b 100644
--- a/drivers/hid/hid-roccat.c
+++ b/drivers/hid/hid-roccat.c
@@ -216,24 +216,19 @@ static int roccat_open(struct inode *inode, struct file *file)
 
 static int roccat_release(struct inode *inode, struct file *file)
 {
-	unsigned int minor = iminor(inode);
 	struct roccat_reader *reader = file->private_data;
-	struct roccat_device *device;
-
-	mutex_lock(&devices_lock);
+	struct roccat_device *device = reader->device;
 
-	device = devices[minor];
-	if (!device) {
-		mutex_unlock(&devices_lock);
-		pr_emerg("roccat device with minor %d doesn't exist\n", minor);
+	if (WARN_ON(!device))
 		return -ENODEV;
-	}
 
 	mutex_lock(&device->readers_lock);
 	list_del(&reader->node);
 	mutex_unlock(&device->readers_lock);
 	kfree(reader);
 
+	mutex_lock(&devices_lock);
+
 	if (!--device->open) {
 		/* removing last reader */
 		if (roccat_device_available(device)) {
-- 
2.55.0