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From: Johan Hovold <johan@kernel.org>
To: Jeremy Kerr <jk@codeconstruct.com.au>,
	Matt Johnston <matt@codeconstruct.com.au>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH] net: mctp: fix device leak on probe failure
Date: Thu,  5 Mar 2026 11:45:49 +0100	[thread overview]
Message-ID: <20260305104549.16110-1-johan@kernel.org> (raw)

Driver core holds a reference to the USB interface and its parent USB
device while the interface is bound to a driver and there is no need to
take additional references unless the structures are needed after
disconnect.

This driver takes a reference to the USB device during probe but does
not to release it on probe failures.

Drop the redundant device reference to fix the leak, reduce cargo
culting, make it easier to spot drivers where an extra reference is
needed, and reduce the risk of further memory leaks.

Fixes: 0791c0327a6e ("net: mctp: Add MCTP USB transport driver")
Cc: stable@vger.kernel.org	# 6.15
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/net/mctp/mctp-usb.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/mctp/mctp-usb.c b/drivers/net/mctp/mctp-usb.c
index ef860cfc629f..3b5dff144177 100644
--- a/drivers/net/mctp/mctp-usb.c
+++ b/drivers/net/mctp/mctp-usb.c
@@ -329,7 +329,7 @@ static int mctp_usb_probe(struct usb_interface *intf,
 	SET_NETDEV_DEV(netdev, &intf->dev);
 	dev = netdev_priv(netdev);
 	dev->netdev = netdev;
-	dev->usbdev = usb_get_dev(interface_to_usbdev(intf));
+	dev->usbdev = interface_to_usbdev(intf);
 	dev->intf = intf;
 	usb_set_intfdata(intf, dev);
 
@@ -365,7 +365,6 @@ static void mctp_usb_disconnect(struct usb_interface *intf)
 	mctp_unregister_netdev(dev->netdev);
 	usb_free_urb(dev->tx_urb);
 	usb_free_urb(dev->rx_urb);
-	usb_put_dev(dev->usbdev);
 	free_netdev(dev->netdev);
 }
 
-- 
2.52.0


             reply	other threads:[~2026-03-05 10:46 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-05 10:45 Johan Hovold [this message]
2026-03-05 23:58 ` [PATCH] net: mctp: fix device leak on probe failure Jeremy Kerr
2026-03-06  1:23   ` Jeremy Kerr
2026-03-07  0:10 ` patchwork-bot+netdevbpf

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