From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: linux/netpoll.h:67 invoked rcu_dereference warning at boot Date: Wed, 22 Sep 2010 15:20:15 +0200 Message-ID: <20100922132014.GA8853@basil.fritz.box> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: netdev@vger.kernel.org Return-path: Received: from one.firstfloor.org ([213.235.205.2]:49239 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752626Ab0IVNUR (ORCPT ); Wed, 22 Sep 2010 09:20:17 -0400 Received: from basil.firstfloor.org (p5B3C9319.dip0.t-ipconnect.de [91.60.147.25]) by one.firstfloor.org (Postfix) with ESMTP id 0336C1A98053 for ; Wed, 22 Sep 2010 15:20:15 +0200 (CEST) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: When booting a recent Linus tree with debugging enabled I get the following warning at boot. I haven't looked into it closely. -Andi =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- /home/lsrc/git/linux-work2/include/linux/netpoll.h:67 invoked rcu_dereferenceeck() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 1 lock held by iceccd/2574: #0: (sk_lock-AF_INET){+.+.+.}, at: [] udp_sendmsg+0x289/00 stack backtrace: Pid: 2574, comm: iceccd Not tainted 2.6.36-rc4-00228-g5647824 #1 Call Trace: [] lockdep_rcu_dereference+0xa4/0xc0 [] netif_rx+0x215/0x240 [] ? cache_alloc_debugcheck_after+0x5f/0x280 [] ? get_parent_ip+0x11/0x50 [] netif_rx_ni+0x23/0x80 [] ip_dev_loopback_xmit+0x83/0xf0 [] ip_mc_output+0x18a/0x220 [] ip_local_out+0x2d/0x80 [] ip_push_pending_frames+0x284/0x420 [] udp_push_pending_frames+0x146/0x3e0 [] ? udp_sendmsg+0x289/0x720 [] udp_sendmsg+0x474/0x720 [] ? local_bh_enable_ip+0x82/0x100 [] inet_sendmsg+0xc4/0x160 [] ? inet_sendmsg+0x0/0x160 [] sock_sendmsg+0xc0/0xf0 [] ? might_fault+0x7a/0xd0 [] ? might_fault+0x7a/0xd0 [] ? might_fault+0xc3/0xd0 [] ? might_fault+0x7a/0xd0 [] ? move_addr_to_kernel+0x50/0x60 [] sys_sendto+0xf5/0x130 [] system_call_fastpath+0x16/0x1b -- ak@linux.intel.com -- Speaking for myself only.