From mboxrd@z Thu Jan 1 00:00:00 1970 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 763D5139D0A for ; Mon, 20 Oct 2025 11:34:55 +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=1760960098; cv=none; b=hiw6JmJp9QmAitc0R5um3qn8IZYv4h2zQqh0qdbltpGSfVEpeDktgiGy/gXwK3mP8cjOhRuCCmSXcz1Fwcb4D9zX7Bee0jv0Mdagg9jpHKJ+6rXCNnYF0jR+TetxvWaHnMXBXc3aVGJgqRPtCFC2/KFSVu38QgIpDtQXBZAvMcs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760960098; c=relaxed/simple; bh=kDNU1VZRvLNKxiiKzrPuVBiAaDGRSLGk5fWfXxh6JGc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=johjcDvi+XwQB8ViEcYaf1etPNH1/tDIc19R6g/4GwgGShh/BPVNQKVMsrsaNixT73AJ2U4U0s1CI43SiaUiC50y1W0ue8aL3MA+aMBVxcgXC7NBBJc9BAE8mMCdrfqR/FbTqBW8EoE5LStCWM7eRdNABRaUPRBrswyu68OY/Ek= 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 1vAoA7-0002j5-Cu; Mon, 20 Oct 2025 13:34:51 +0200 Received: from moin.white.stw.pengutronix.de ([2a0a:edc0:0:b01:1d::7b] helo=bjornoya.blackshift.org) 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 1vAoA7-004XYw-01; Mon, 20 Oct 2025 13:34:51 +0200 Received: from hardanger.blackshift.org (p54b152ce.dip0.t-ipconnect.de [84.177.82.206]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: mkl-all@blackshift.org) by smtp.blackshift.org (Postfix) with ESMTPSA id B055D48B1A3; Mon, 20 Oct 2025 11:34:50 +0000 (UTC) From: Marc Kleine-Budde Date: Mon, 20 Oct 2025 13:34:42 +0200 Subject: [PATCH can] can: netlink: can_changelink(): allow disabling of automatic restart Precedence: bulk X-Mailing-List: linux-can@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251020-netlink-fix-restart-v1-1-3f53c7f8520b@pengutronix.de> X-B4-Tracking: v=1; b=H4sIAFEe9mgC/x2MSQqAMAwAvyI5G2jrgvoV8VA0alCipEUE8e8Wj 8Mw80AgZQrQZQ8oXRz4kAQ2z2BcvSyEPCUGZ1xljTMoFHeWDWe+USlErxFrY+u5nNqCigZSeSo l/V97GL3A8L4f6U2h9GoAAAA= X-Change-ID: 20251020-netlink-fix-restart-6016f4d93e38 To: Vincent Mailhol Cc: kernel@pengutronix.de, linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Andrei Lalaev , Marc Kleine-Budde X-Mailer: b4 0.15-dev-2196b X-Developer-Signature: v=1; a=openpgp-sha256; l=2586; i=mkl@pengutronix.de; h=from:subject:message-id; bh=kDNU1VZRvLNKxiiKzrPuVBiAaDGRSLGk5fWfXxh6JGc=; b=owEBbQGS/pANAwAKAQx0Zd/5kJGcAcsmYgBo9h5X2JCZcavGBOSF3ZCtEzlQmXp4FZ8rv1spy JxOqBUEyjSJATMEAAEKAB0WIQSf+wzYr2eoX/wVbPMMdGXf+ZCRnAUCaPYeVwAKCRAMdGXf+ZCR nKr/CACy7MaS9SyKjY3LpHAmw2cp2qqwGHjVYgqGKh3GN6iNMtMAH5cq1nbOAChjFszbUWQwZGY 105ATKqqDtpDNgH4jgvbobkuHOTNQOOi4tc8Netwu88b+bJPcDSjbp5MypKYHrbyae3cYpr7ro8 GmH0pG0nW10iIaNA1Tm2AE+huoClGFdvVQ1ukVzDrhqzv7g83pG3Rj0uFWFssASqy5hg+TLONn6 q2oS6EqMzJ4KgRhLJLaG8U5ELJ881fCNhu3QSUIXTCraUCt0OVPFaSJCObDWHmVQNGs4shP4j8P ZGyW4o9HbEP/37lYMJEfnhHstiddj9zf47Z0d4UZu33fNzzM X-Developer-Key: i=mkl@pengutronix.de; a=openpgp; fpr=C1400BA0B3989E6FBC7D5B5C2B5EE211C58AEA54 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-can@vger.kernel.org Since the commit c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode"), the automatic restart delay can only be set for devices that implement the restart handler struct can_priv::do_set_mode. As it makes no sense to configure a automatic restart for devices that doesn't support it. However, since systemd commit 13ce5d4632e3 ("network/can: properly handle CAN.RestartSec=0") [1], systemd-networkd correctly handles a restart delay of "0" (i.e. the restart is disabled). Which means that a disabled restart is always configured in the kernel. On systems with both changes active this causes that CAN interfaces that don't implement a restart handler cannot be brought up by systemd-networkd. Solve this problem by allowing a delay of "0" to be configured, even if the device does not implement a restart handler. [1] https://github.com/systemd/systemd/commit/13ce5d4632e395521e6205c954493c7fc1c4c6e0 Cc: stable@vger.kernel.org Cc: Andrei Lalaev Reported-by: Marc Kleine-Budde Closes: https://lore.kernel.org/all/20251020-certain-arrogant-vole-of-sunshine-141841-mkl@pengutronix.de Fixes: c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode") Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev/netlink.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c index 0591406b6f32..6f83b87d54fc 100644 --- a/drivers/net/can/dev/netlink.c +++ b/drivers/net/can/dev/netlink.c @@ -452,7 +452,9 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], } if (data[IFLA_CAN_RESTART_MS]) { - if (!priv->do_set_mode) { + unsigned int restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]); + + if (restart_ms != 0 && !priv->do_set_mode) { NL_SET_ERR_MSG(extack, "Device doesn't support restart from Bus Off"); return -EOPNOTSUPP; @@ -461,7 +463,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], /* Do not allow changing restart delay while running */ if (dev->flags & IFF_UP) return -EBUSY; - priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]); + priv->restart_ms = restart_ms; } if (data[IFLA_CAN_RESTART]) { --- base-commit: ffff5c8fc2af2218a3332b3d5b97654599d50cde change-id: 20251020-netlink-fix-restart-6016f4d93e38 Best regards, -- Marc Kleine-Budde