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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C120CC352A3 for ; Mon, 10 Feb 2020 13:11:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99AFF20714 for ; Mon, 10 Feb 2020 13:11:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581340319; bh=pBNVe5B5TuxLtTBe56iYx6Q7FVo7ZnEtWgxBdzTyK7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wMSI9IVjU1u3qTmK6qvacJv5slw0Fv05Qi3fRfBAekZdLiw8o7Ua+QsBlxQqsaEBY I08zODcc92mowHSF3QeJ1GcXDnvnyxftYMRLL8u3qR696brGFP2fi+rsCPeXK503IB 4Lo7CgTAsEzwJXb4CcHLRCLFrL9rGrLDHMHB82zs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729331AbgBJNLy (ORCPT ); Mon, 10 Feb 2020 08:11:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:35614 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728325AbgBJMi5 (ORCPT ); Mon, 10 Feb 2020 07:38:57 -0500 Received: from localhost (unknown [209.37.97.194]) (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 B03C020842; Mon, 10 Feb 2020 12:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338336; bh=pBNVe5B5TuxLtTBe56iYx6Q7FVo7ZnEtWgxBdzTyK7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G8lqpPDU51GpKSyESEA/pt1nFMlFC01aHHyrnin/aVJit8QdkQrXCc92yJErtMN5D DYuyaLzYqKETaH19q4Rs3/PpNzoB5zQH7sEg8deTSLmeokyjcCSw6eiiIU79351sfI j+99+GqaTyBdyrpcVBZbcp9DXSupC/5IDD4zDlI4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , Jiri Pirko , "David S. Miller" Subject: [PATCH 5.4 284/309] drop_monitor: Do not cancel uninitialized work item Date: Mon, 10 Feb 2020 04:34:00 -0800 Message-Id: <20200210122433.937537135@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122406.106356946@linuxfoundation.org> References: <20200210122406.106356946@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ido Schimmel [ Upstream commit dfa7f709596be5ca46c070d4f8acbb344322056a ] Drop monitor uses a work item that takes care of constructing and sending netlink notifications to user space. In case drop monitor never started to monitor, then the work item is uninitialized and not associated with a function. Therefore, a stop command from user space results in canceling an uninitialized work item which leads to the following warning [1]. Fix this by not processing a stop command if drop monitor is not currently monitoring. [1] [ 31.735402] ------------[ cut here ]------------ [ 31.736470] WARNING: CPU: 0 PID: 143 at kernel/workqueue.c:3032 __flush_work+0x89f/0x9f0 ... [ 31.738120] CPU: 0 PID: 143 Comm: dwdump Not tainted 5.5.0-custom-09491-g16d4077796b8 #727 [ 31.741968] RIP: 0010:__flush_work+0x89f/0x9f0 ... [ 31.760526] Call Trace: [ 31.771689] __cancel_work_timer+0x2a6/0x3b0 [ 31.776809] net_dm_cmd_trace+0x300/0xef0 [ 31.777549] genl_rcv_msg+0x5c6/0xd50 [ 31.781005] netlink_rcv_skb+0x13b/0x3a0 [ 31.784114] genl_rcv+0x29/0x40 [ 31.784720] netlink_unicast+0x49f/0x6a0 [ 31.787148] netlink_sendmsg+0x7cf/0xc80 [ 31.790426] ____sys_sendmsg+0x620/0x770 [ 31.793458] ___sys_sendmsg+0xfd/0x170 [ 31.802216] __sys_sendmsg+0xdf/0x1a0 [ 31.806195] do_syscall_64+0xa0/0x540 [ 31.806885] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 8e94c3bc922e ("drop_monitor: Allow user to start monitoring hardware drops") Signed-off-by: Ido Schimmel Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/drop_monitor.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -1004,8 +1004,10 @@ static void net_dm_hw_monitor_stop(struc { int cpu; - if (!monitor_hw) + if (!monitor_hw) { NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); + return; + } monitor_hw = false;