From patchwork Thu Mar 19 13:04:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 229032 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CEF9C4332B for ; Thu, 19 Mar 2020 13:28:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E66512080C for ; Thu, 19 Mar 2020 13:28:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624482; bh=vxseYOJeQCS6fWbwxaaYEYi2MoV+stP5GL0I0dHdpzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wAzOS1ngoAipsWWgThf8JN4ByH6IKtart98542XrvZeAN5jE6fPe9EU7EHxLsBp7V r8h1pAZ4LRw4uCTlhT7cFzVhCE0Gdh1erhLXTp+14RZXMRPBPuFUCae2YgaDs5wBe9 PjHUcVdVgu9vfH/gQ2leMXlkivVvvbub625+S01Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730977AbgCSN2A (ORCPT ); Thu, 19 Mar 2020 09:28:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:56528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730971AbgCSN2A (ORCPT ); Thu, 19 Mar 2020 09:28:00 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 650AF2080C; Thu, 19 Mar 2020 13:27:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584624478; bh=vxseYOJeQCS6fWbwxaaYEYi2MoV+stP5GL0I0dHdpzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LazX3j+roJopGq7AsF2RhF3vougycIJEHdBolNVH87Ca5wlgJZWP3aQULTc1iEhqO kVvJKTznqznp58NCPaq2qn8yRtIe+R0UAOJlfX+lQJsV6jL3PloqBmcZ9DswrlXqGp TMZXm80nTtzHEVs7HoDNp2tt1q49eHP3PBUqKMS0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Taehee Yoo , "David S. Miller" , Sasha Levin Subject: [PATCH 5.5 49/65] net: rmnet: remove rcu_read_lock in rmnet_force_unassociate_device() Date: Thu, 19 Mar 2020 14:04:31 +0100 Message-Id: <20200319123941.803097321@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123926.466988514@linuxfoundation.org> References: <20200319123926.466988514@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Taehee Yoo [ Upstream commit c026d970102e9af9958edefb4a015702c6aab636 ] The notifier_call() of the slave interface removes rmnet interface with unregister_netdevice_queue(). But, before calling unregister_netdevice_queue(), it acquires rcu readlock. In the RCU critical section, sleeping isn't be allowed. But, unregister_netdevice_queue() internally calls synchronize_net(), which would sleep. So, suspicious RCU usage warning occurs. Test commands: modprobe rmnet ip link add dummy0 type dummy ip link add dummy1 type dummy ip link add rmnet0 link dummy0 type rmnet mux_id 1 ip link set dummy1 master rmnet0 ip link del dummy0 Splat looks like: [ 79.639245][ T1195] ============================= [ 79.640134][ T1195] WARNING: suspicious RCU usage [ 79.640852][ T1195] 5.6.0-rc1+ #447 Not tainted [ 79.641657][ T1195] ----------------------------- [ 79.642472][ T1195] ./include/linux/rcupdate.h:273 Illegal context switch in RCU read-side critical section! [ 79.644043][ T1195] [ 79.644043][ T1195] other info that might help us debug this: [ 79.644043][ T1195] [ 79.645682][ T1195] [ 79.645682][ T1195] rcu_scheduler_active = 2, debug_locks = 1 [ 79.646980][ T1195] 2 locks held by ip/1195: [ 79.647629][ T1195] #0: ffffffffa3cf64f0 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x457/0x890 [ 79.649312][ T1195] #1: ffffffffa39256c0 (rcu_read_lock){....}, at: rmnet_config_notify_cb+0xf0/0x590 [rmnet] [ 79.651717][ T1195] [ 79.651717][ T1195] stack backtrace: [ 79.652650][ T1195] CPU: 3 PID: 1195 Comm: ip Not tainted 5.6.0-rc1+ #447 [ 79.653702][ T1195] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 79.655037][ T1195] Call Trace: [ 79.655560][ T1195] dump_stack+0x96/0xdb [ 79.656252][ T1195] ___might_sleep+0x345/0x440 [ 79.656994][ T1195] synchronize_net+0x18/0x30 [ 79.661132][ T1195] netdev_rx_handler_unregister+0x40/0xb0 [ 79.666266][ T1195] rmnet_unregister_real_device+0x42/0xb0 [rmnet] [ 79.667211][ T1195] rmnet_config_notify_cb+0x1f7/0x590 [rmnet] [ 79.668121][ T1195] ? rmnet_unregister_bridge.isra.6+0xf0/0xf0 [rmnet] [ 79.669166][ T1195] ? rmnet_unregister_bridge.isra.6+0xf0/0xf0 [rmnet] [ 79.670286][ T1195] ? __module_text_address+0x13/0x140 [ 79.671139][ T1195] notifier_call_chain+0x90/0x160 [ 79.671973][ T1195] rollback_registered_many+0x660/0xcf0 [ 79.672893][ T1195] ? netif_set_real_num_tx_queues+0x780/0x780 [ 79.675091][ T1195] ? __lock_acquire+0xdfe/0x3de0 [ 79.675825][ T1195] ? memset+0x1f/0x40 [ 79.676367][ T1195] ? __nla_validate_parse+0x98/0x1ab0 [ 79.677290][ T1195] unregister_netdevice_many.part.133+0x13/0x1b0 [ 79.678163][ T1195] rtnl_delete_link+0xbc/0x100 [ ... ] Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c index fc68ecdd804bc..0ad64aa665925 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -230,7 +230,6 @@ static void rmnet_force_unassociate_device(struct net_device *dev) port = rmnet_get_port_rtnl(dev); - rcu_read_lock(); rmnet_unregister_bridge(dev, port); hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) { @@ -241,7 +240,6 @@ static void rmnet_force_unassociate_device(struct net_device *dev) kfree(ep); } - rcu_read_unlock(); unregister_netdevice_many(&list); rmnet_unregister_real_device(real_dev, port);