From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Jones Subject: suspicious rcu_dereference in tcp_v6_send_synack Date: Thu, 7 Jan 2016 10:32:48 -0500 Message-ID: <20160107153248.GA30472@codemonkey.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: netdev@vger.kernel.org Return-path: Received: from arcturus.aphlor.org ([188.246.204.175]:48622 "EHLO arcturus.aphlor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752849AbcAGPcu (ORCPT ); Thu, 7 Jan 2016 10:32:50 -0500 Received: from [209.6.119.210] (helo=wopr.kernelslacker.org) by arcturus.aphlor.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.86) (envelope-from ) id 1aHCYT-0008I8-CT for netdev@vger.kernel.org; Thu, 07 Jan 2016 15:32:49 +0000 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: =============================== [ INFO: suspicious RCU usage. ] 4.4.0-rc8-firewall+ #1 Not tainted ------------------------------- net/ipv6/tcp_ipv6.c:465 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 1 lock held by swapper/1/0: #0: (((&req->rsk_timer))){+.-...}, at: [] call_timer_fn+0x5/0x3f0 stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.0-rc8-firewall+ #1 0000000000000000 ffff8801d7a07b28 ffffffff9948b3b5 ffff8801d6046500 ffff8801d7a07b58 ffffffff990e9b7a ffff8801cd356240 0000000000000000 ffff8801d23b1698 ffff8801d23b0c40 ffff8801d7a07ba8 ffffffff99b635d2 Call Trace: [] dump_stack+0x4e/0x79 [] lockdep_rcu_suspicious+0xea/0x110 [] tcp_v6_send_synack+0x2c2/0x350 [] tcp_rtx_synack+0xdd/0x180 [] ? tcp_send_probe0+0x1a0/0x1a0 [] reqsk_timer_handler+0x4c4/0x530 [] ? inet_csk_reqsk_queue_drop+0x3a0/0x3a0 [] ? __lock_is_held+0x9b/0xd0 [] call_timer_fn+0x132/0x3f0 [] ? call_timer_fn+0x5/0x3f0 [] ? inet_csk_reqsk_queue_drop+0x3a0/0x3a0 [] ? process_timeout+0x10/0x10 [] ? trace_hardirqs_on_caller+0x192/0x2a0 [] ? preempt_count_sub+0x1a/0x130 [] run_timer_softirq+0x47b/0x590 [] ? inet_csk_reqsk_queue_drop+0x3a0/0x3a0 [] ? internal_add_timer+0x110/0x110 [] ? __lock_is_held+0x28/0xd0 [] __do_softirq+0x1b2/0x5c0 [] irq_exit+0xfc/0x110 [] smp_apic_timer_interrupt+0x5f/0x70 [] apic_timer_interrupt+0x8b/0x90 [] ? cpuidle_enter_state+0x1c7/0x460 [] ? cpuidle_enter_state+0x1c2/0x460 [] ? rcu_eqs_enter_common+0x139/0x280 [] cpuidle_enter+0x17/0x20 [] cpu_startup_entry+0x4d2/0x5b0 [] ? default_idle_call+0x60/0x60 [] ? clockevents_config_and_register+0x64/0x70 [] ? setup_APIC_timer+0x115/0x120 [] start_secondary+0x23a/0x2a0 [] ? set_cpu_sibling_map+0x9c0/0x9c0