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USB: serial: digi_acceleport: add port lock nesting annotation

PATCH New Johan Hovold 1 participant 1 message Aug 1

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Johan Hovold

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#0 lore raw

PATCH 1/1 USB: serial: digi_acceleport: add port lock nesting annotation

The driver takes the driver port lock of both the OOB port and the port itself when setting the modem control signals, which confuses lockdep.

Mark the OOB port lock as belonging to a separate subclass to suppress false positive lockdep deadlock warnings.

Reported-by [email protected]
Link https://lore.kernel.org/all/[email protected]/ open here
Signed-off-by Johan Hovold <[email protected]>
---
 drivers/usb/serial/digi_acceleport.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
drivers/usb/serial/digi_acceleport.c +7 -2
index dea039163661..911d74f20f0e 100644
@@ -1228,6 +1228,7 @@ static int digi_startup_device(struct usb_serial *serial)
 
 static int digi_port_init(struct usb_serial_port *port, unsigned port_num)
 {
+	struct digi_serial *serial_priv = usb_get_serial_data(port->serial);
 	struct digi_port *priv;
 
 	priv = kzalloc_obj(*priv);

@@ -1235,6 +1236,10 @@ static int digi_port_init(struct usb_serial_port *port, unsigned port_num)
 		return -ENOMEM;
 
 	spin_lock_init(&priv->dp_port_lock);
+
+	if (port == serial_priv->ds_oob_port)
+		lockdep_set_subclass(&priv->dp_port_lock, SINGLE_DEPTH_NESTING);
+
 	priv->dp_port_num = port_num;
 	init_waitqueue_head(&priv->dp_transmit_idle_wait);
 	init_waitqueue_head(&priv->dp_flush_wait);

@@ -1279,6 +1284,8 @@ static int digi_startup(struct usb_serial *serial)
 	serial_priv->ds_oob_port_num = oob_port_num;
 	serial_priv->ds_oob_port = serial->port[oob_port_num];
 
+	usb_set_serial_data(serial, serial_priv);
+
 	ret = digi_port_init(serial_priv->ds_oob_port,
 						serial_priv->ds_oob_port_num);
 	if (ret) {

@@ -1286,8 +1293,6 @@ static int digi_startup(struct usb_serial *serial)
 		return ret;
 	}
 
-	usb_set_serial_data(serial, serial_priv);
-
 	return 0;
 }
Signature · 1 line
2.54.0