From nobody Thu Apr 9 23:26:09 2026 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 12A271A262D for ; Thu, 5 Mar 2026 14:34:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772721281; cv=none; b=QUgbpemlHJ6rTOOyiDyKPf6YXlCX2u5L/jgjj5rnc9hLZTQ71fxRLvPTIzWP3WIHW+J88KvSkHN/rBb6bU8El3Kp0QaAM48678le8nzgXV2z5UI9RKO/tGXmxuMCfyRd+3Va/FncQeGb274d9XucumsegXkVKyT7CZGEPq7Ft+g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772721281; c=relaxed/simple; bh=1fnU0MUKwFDu+HuPm2g0JEOYCoHt7uKd2I73uTFW9+s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pQJb+NcvgtpOIkTaG8GIZhKMaJ9RJh8u/cpWE0MgKuo4jYNX+r2RTagVEa7q8kzUj3RveJj3sCZi9yk7drd+ZrTP2e6zqxlg/b1W9FOYzHJ6BigDHFskeXT+oaDUyVVRE5+QBNA8gFHewCIK5ATfTxhpzRouq9OWuq8+dosbw3E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1vy9mZ-000464-Pm; Thu, 05 Mar 2026 15:34:31 +0100 Received: from dude04.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::ac] helo=dude04) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vy9mX-003two-2B; Thu, 05 Mar 2026 15:34:31 +0100 Received: from ore by dude04 with local (Exim 4.98.2) (envelope-from ) id 1vy9mY-00000002E8c-3zeM; Thu, 05 Mar 2026 15:34:30 +0100 From: Oleksij Rempel To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Woojung Huh , Andrew Lunn , Thangaraj Samynathan , Rengarajan Sundararajan Cc: Oleksij Rempel , stable@vger.kernel.org, kernel@pengutronix.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, UNGLinuxDriver@microchip.com Subject: [PATCH net v1 4/4] net: usb: lan78xx: fix WARN in __netif_napi_del_locked on disconnect Date: Thu, 5 Mar 2026 15:34:29 +0100 Message-ID: <20260305143429.530909-5-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260305143429.530909-1-o.rempel@pengutronix.de> References: <20260305143429.530909-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Remove redundant netif_napi_del() call from disconnect path. A WARN may be triggered in __netif_napi_del_locked() during USB device disconnect: WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x= 2b4/0x350 This happens because netif_napi_del() is called in the disconnect path while NAPI is still enabled. However, it is not necessary to call netif_napi_del() explicitly, since unregister_netdev() will handle NAPI teardown automatical= ly and safely. Removing the redundant call avoids triggering the warning. Full trace: lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret =3D -E= NODEV lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV lan78xx 1-1:1.0 enu1: Link is Down lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret =3D -E= NODEV ------------[ cut here ]------------ WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2= b4/0x350 Modules linked in: flexcan can_dev fuse CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926= 949dab03 #9 PREEMPT Hardware name: SKOV IMX8MP CPU revC - bd500 (DT) Workqueue: usb_hub_wq hub_event pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=3D--) pc : __netif_napi_del_locked+0x2b4/0x350 lr : __netif_napi_del_locked+0x7c/0x350 sp : ffffffc085b673c0 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000 Call trace: __netif_napi_del_locked+0x2b4/0x350 (P) lan78xx_disconnect+0xf4/0x360 usb_unbind_interface+0x158/0x718 device_remove+0x100/0x150 device_release_driver_internal+0x308/0x478 device_release_driver+0x1c/0x30 bus_remove_device+0x1a8/0x368 device_del+0x2e0/0x7b0 usb_disable_device+0x244/0x540 usb_disconnect+0x220/0x758 hub_event+0x105c/0x35e0 process_one_work+0x760/0x17b0 worker_thread+0x768/0xce8 kthread+0x3bc/0x690 ret_from_fork+0x10/0x20 irq event stamp: 211604 hardirqs last enabled at (211603): [] _raw_spin_unlock_= irqrestore+0x84/0x98 hardirqs last disabled at (211604): [] el1_dbg+0x24/0x80 softirqs last enabled at (211296): [] handle_softirqs+0= x820/0xbc8 softirqs last disabled at (210993): [] __do_softirq+0x18= /0x20 ---[ end trace 0000000000000000 ]--- lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0 Fixes: e110bc825897 ("net: usb: lan78xx: Convert to PHYLINK for improved PH= Y and MAC management") Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel --- changes v2: - Do not move NAPI enable/disable to link up/down callbacks. - Remove redundant netif_napi_del() call from disconnect path. - Update commit message to accurately describe the root cause and solution, following feedback from maintainer. --- drivers/net/usb/lan78xx.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index f8558b87eaec..19cdf69fa589 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -4552,8 +4552,6 @@ static void lan78xx_disconnect(struct usb_interface *= intf) phylink_disconnect_phy(dev->phylink); rtnl_unlock(); =20 - netif_napi_del(&dev->napi); - unregister_netdev(net); =20 timer_shutdown_sync(&dev->stat_monitor); --=20 2.47.3