From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEE54C072A2 for ; Wed, 15 Nov 2023 20:44:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233525AbjKOUoo (ORCPT ); Wed, 15 Nov 2023 15:44:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233534AbjKOUon (ORCPT ); Wed, 15 Nov 2023 15:44:43 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06763A1 for ; Wed, 15 Nov 2023 12:44:40 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D0D0C433C7; Wed, 15 Nov 2023 20:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700081079; bh=bZeBol5rVjr6PNJXLG3AC31YPG0sf+0cBdwXcjgH3Go=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a5sbxijYvJmLbWoi+GViUKv2eaMSocQha38KD9K48MMlvj3T71L2zdk2SEULjD2FR rd589hlthxOSUY5VMFElGAEapRbmoJiudSqsmfiMUPKYFgrkTcCNVcIOFhHvZYngP9 e2MGZ4oUhdERrb8AGoDk+I8a7/zkcxvhp/qWAjb8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vincent Mailhol , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 4.19 09/88] can: dev: can_restart(): dont crash kernel if carrier is OK Date: Wed, 15 Nov 2023 15:35:21 -0500 Message-ID: <20231115191426.749179928@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115191426.221330369@linuxfoundation.org> References: <20231115191426.221330369@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marc Kleine-Budde [ Upstream commit fe5c9940dfd8ba0c73672dddb30acd1b7a11d4c7 ] During testing, I triggered a can_restart() with the netif carrier being OK [1]. The BUG_ON, which checks if the carrier is OK, results in a fatal kernel crash. This is neither helpful for debugging nor for a production system. [1] The root cause is a race condition in can_restart() which will be fixed in the next patch. Do not crash the kernel, issue an error message instead, and continue restarting the CAN device anyway. Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Link: https://lore.kernel.org/all/20231005-can-dev-fix-can-restart-v2-1-91b5c1fd922c@pengutronix.de Reviewed-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- drivers/net/can/dev/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c index 8738d37f72737..487cb9acdd456 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -563,7 +563,8 @@ static void can_restart(struct net_device *dev) struct can_frame *cf; int err; - BUG_ON(netif_carrier_ok(dev)); + if (netif_carrier_ok(dev)) + netdev_err(dev, "Attempt to restart for bus-off recovery, but carrier is OK?\n"); /* * No synchronization needed because the device is bus-off and -- 2.42.0