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 D8F151C08 for ; Wed, 28 Dec 2022 16:36:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CF3AC433D2; Wed, 28 Dec 2022 16:36:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672245382; bh=ymDt+OQ1d1l7JhA36+wNvf/5kqDthP0wuJ+WVC+JCpo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dbMo8cVjH1mXF6EM05aIiw3rRjuDuoOgQXVT9SB46W9pCSkZnhBAY7fjYiuBXOxp5 rYSq/AMMg26lscZ8f+lXC6wkMAy9UPzQEXAqd6/ysAqd6jdFhsOdLVCN/srThANkFV FxkuEui6mO0KIJB9WKtTVnEjDe8X/wjSJKfpfcXo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Matt Johnston , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.0 0883/1073] mctp: Remove device type check at unregister Date: Wed, 28 Dec 2022 15:41:11 +0100 Message-Id: <20221228144352.011134374@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221228144328.162723588@linuxfoundation.org> References: <20221228144328.162723588@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Matt Johnston [ Upstream commit b389a902dd5be4ece505a2e0463b9b034de04bf5 ] The unregister check could be incorrectly triggered if a netdev changes its type after register. That is possible for a tun device using TUNSETLINK ioctl, resulting in mctp unregister failing and the netdev unregister waiting forever. This was encountered by https://github.com/openthread/openthread/issues/8523 Neither check at register or unregister is required. They were added in an attempt to track down mctp_ptr being set unexpectedly, which should not happen in normal operation. Fixes: 7b1871af75f3 ("mctp: Warn if pointer is set for a wrong dev type") Signed-off-by: Matt Johnston Link: https://lore.kernel.org/r/20221215054933.2403401-1-matt@codeconstruct.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/mctp/device.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) diff --git a/net/mctp/device.c b/net/mctp/device.c index 99a3bda8852f..acb97b257428 100644 --- a/net/mctp/device.c +++ b/net/mctp/device.c @@ -429,12 +429,6 @@ static void mctp_unregister(struct net_device *dev) struct mctp_dev *mdev; mdev = mctp_dev_get_rtnl(dev); - if (mdev && !mctp_known(dev)) { - // Sanity check, should match what was set in mctp_register - netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d", - __func__, dev->type); - return; - } if (!mdev) return; @@ -451,14 +445,8 @@ static int mctp_register(struct net_device *dev) struct mctp_dev *mdev; /* Already registered? */ - mdev = rtnl_dereference(dev->mctp_ptr); - - if (mdev) { - if (!mctp_known(dev)) - netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d", - __func__, dev->type); + if (rtnl_dereference(dev->mctp_ptr)) return 0; - } /* only register specific types */ if (!mctp_known(dev)) -- 2.35.1