From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0E73443AB6 for ; Wed, 15 Nov 2023 20:47:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yvoDiHX4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3B11C43397; Wed, 15 Nov 2023 20:47:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700081235; bh=F/N1DP5OvulV5y91/7h8wM5KloaUwAWmojhBxMXjaeA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yvoDiHX408uGhNKDirBjjfcCChlhagiSINq9sh8fzV/9Vp22UNK2b//8CpScIQyL3 Z+dxNhFPbjB2/Ywk/qfiwxmedJdOaHwZGR2N/r1ET1Gle5Ec75JyC3Pr7jmib/4mp3 wdL/WQBKU2q3GZ+s+uvFNSGSCG5M1T1RHb8XNpcg= 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 5.15 033/244] can: dev: can_restart(): dont crash kernel if carrier is OK Date: Wed, 15 Nov 2023 15:33:45 -0500 Message-ID: <20231115203550.365075173@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115203548.387164783@linuxfoundation.org> References: <20231115203548.387164783@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-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 e3d840b81357d..ed2841a681d72 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -141,7 +141,8 @@ 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 * no messages can come in or go out. -- 2.42.0