Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757378Ab0DWMvF (ORCPT ); Fri, 23 Apr 2010 08:51:05 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:50766 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752631Ab0DWMvA (ORCPT ); Fri, 23 Apr 2010 08:51:00 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=vRKARjktg+cwhDdhfdWyY9Sq4Ih+i91RUT6D0MkYrmxdG6fYoHMPkKopACERijrr3w AG+GaxjalyiYKlQQXY+81WHle2pBttg6W6bN4Llh4VXEJPXaNNdui6vaPh7mGZIC2Bh+ 6wNDzQCjvsI2ivUx8Nf73q5LspQFRs2iz+pdI= MIME-Version: 1.0 In-Reply-To: <20100422160144.GC2524@linux.vnet.ibm.com> References: <20100419230136.GA16856@linux.vnet.ibm.com> <20100420030452.GB2905@linux.vnet.ibm.com> <4BCD646B.1080206@cn.fujitsu.com> <1271766716.2972.16.camel@dhcp231-113.rdu.redhat.com> <20100420135227.GC2628@linux.vnet.ibm.com> <20100421213543.GO2563@linux.vnet.ibm.com> <20100422145640.GB3228@redhat.com> <20100422160144.GC2524@linux.vnet.ibm.com> Date: Fri, 23 Apr 2010 08:50:59 -0400 Message-ID: Subject: Re: [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage From: Miles Lane To: paulmck@linux.vnet.ibm.com Cc: Vivek Goyal , Eric Paris , Lai Jiangshan , Ingo Molnar , Peter Zijlstra , LKML , nauman@google.com, eric.dumazet@gmail.com, netdev@vger.kernel.org, Jens Axboe , Gui Jianfeng , Li Zefan Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6306 Lines: 114 Hi Paul, There has been a bit of back and forth, and I am not sure what patches I should test now. Could you send me a bundle of whatever needs testing now? I currently have a build of 2.6.34-rc5-git3 with the same patch I tested before applied. I notice a few minor differences in the warnings given. I suspect these do not indicate new issues, since the trace from through is the same as before. [ 60.174809] [ INFO: suspicious rcu_dereference_check() usage. ] [ 60.174812] --------------------------------------------------- [ 60.174816] net/mac80211/sta_info.c:886 invoked rcu_dereference_check() without protection! [ 60.174820] [ 60.174821] other info that might help us debug this: [ 60.174822] [ 60.174825] [ 60.174826] rcu_scheduler_active = 1, debug_locks = 1 [ 60.174829] no locks held by wpa_supplicant/3973. [ 60.174832] [ 60.174833] stack backtrace: [ 60.174838] Pid: 3973, comm: wpa_supplicant Not tainted 2.6.34-rc5-git3 #19 [ 60.174841] Call Trace: [ 60.174844] [] lockdep_rcu_dereference+0x9d/0xa5 [ 60.174873] [] ieee80211_find_sta_by_hw+0x46/0x10f [mac80211] [ 60.174886] [] ieee80211_find_sta+0x17/0x19 [mac80211] [ 60.174902] [] iwl_tx_queue_reclaim+0xdb/0x1b1 [iwlcore] [ 60.174909] [] ? mark_lock+0x2d/0x235 [ 60.174920] [] iwl5000_rx_reply_tx+0x4a9/0x556 [iwlagn] [ 60.174927] [] ? is_swiotlb_buffer+0x2e/0x3b [ 60.174936] [] iwl_rx_handle+0x163/0x2b5 [iwlagn] [ 60.174943] [] ? trace_hardirqs_on_caller+0xfa/0x13f [ 60.174952] [] iwl_irq_tasklet+0x2bb/0x3c0 [iwlagn] [ 60.174959] [] tasklet_action+0xa7/0x10f [ 60.174965] [] __do_softirq+0x144/0x252 [ 60.174972] [] call_softirq+0x1c/0x34 [ 60.174977] [] do_softirq+0x38/0x80 [ 60.174982] [] irq_exit+0x45/0x94 [ 60.174987] [] do_IRQ+0xad/0xc4 [ 60.174994] [] ret_from_intr+0x0/0xf [ 60.174997] [] ? kmem_cache_alloc+0xa9/0x15f [ 60.175010] [] ? __alloc_skb+0x3d/0x155 [ 60.175016] [] __alloc_skb+0x3d/0x155 [ 60.175023] [] sock_alloc_send_pskb+0xc0/0x2e5 [ 60.175030] [] sock_alloc_send_skb+0x10/0x12 [ 60.175036] [] unix_stream_sendmsg+0x117/0x2e2 [ 60.175044] [] ? avc_has_perm+0x57/0x69 [ 60.175050] [] ? sock_aio_write+0x0/0xcf [ 60.175056] [] __sock_sendmsg+0x59/0x64 [ 60.175062] [] sock_aio_write+0xbb/0xcf [ 60.175069] [] do_sync_readv_writev+0xbc/0xfb [ 60.175077] [] ? selinux_file_permission+0xa2/0xaf [ 60.175082] [] ? copy_from_user+0x2a/0x2c [ 60.175089] [] ? security_file_permission+0x11/0x13 [ 60.175095] [] do_readv_writev+0xa2/0x122 [ 60.175101] [] ? fcheck_files+0x8f/0xc9 [ 60.175107] [] vfs_writev+0x3e/0x49 [ 60.175113] [] sys_writev+0x45/0x8e [ 60.175119] [] system_call_fastpath+0x16/0x1b [ 60.223213] [ INFO: suspicious rcu_dereference_check() usage. ] [ 60.223216] --------------------------------------------------- [ 60.223221] net/mac80211/sta_info.c:886 invoked rcu_dereference_check() without protection! [ 60.223224] [ 60.223225] other info that might help us debug this: [ 60.223227] [ 60.223230] [ 60.223230] rcu_scheduler_active = 1, debug_locks = 1 [ 60.223234] no locks held by udisks-daemon/4398. [ 60.223236] [ 60.223237] stack backtrace: [ 60.223242] Pid: 4398, comm: udisks-daemon Not tainted 2.6.34-rc5-git3 #19 [ 60.223245] Call Trace: [ 60.223249] [] lockdep_rcu_dereference+0x9d/0xa5 [ 60.223275] [] ieee80211_find_sta_by_hw+0x96/0x10f [mac80211] [ 60.223288] [] ieee80211_find_sta+0x17/0x19 [mac80211] [ 60.223304] [] iwl_tx_queue_reclaim+0xdb/0x1b1 [iwlcore] [ 60.223310] [] ? mark_lock+0x2d/0x235 [ 60.223321] [] iwl5000_rx_reply_tx+0x4a9/0x556 [iwlagn] [ 60.223329] [] ? is_swiotlb_buffer+0x2e/0x3b [ 60.223338] [] iwl_rx_handle+0x163/0x2b5 [iwlagn] [ 60.223344] [] ? trace_hardirqs_on_caller+0xfa/0x13f [ 60.223353] [] iwl_irq_tasklet+0x2bb/0x3c0 [iwlagn] [ 60.223360] [] tasklet_action+0xa7/0x10f [ 60.223367] [] __do_softirq+0x144/0x252 [ 60.223374] [] call_softirq+0x1c/0x34 [ 60.223379] [] do_softirq+0x38/0x80 [ 60.223384] [] irq_exit+0x45/0x94 [ 60.223389] [] do_IRQ+0xad/0xc4 [ 60.223396] [] ret_from_intr+0x0/0xf [ 60.223399] [] ? kmem_cache_free+0xb0/0x134 [ 60.223412] [] ? putname+0x2d/0x36 [ 60.223417] [] putname+0x2d/0x36 [ 60.223423] [] user_path_at+0x5f/0x8e [ 60.223429] [] ? mark_held_locks+0x52/0x70 [ 60.223435] [] ? kmem_cache_free+0xad/0x134 [ 60.223441] [] ? trace_hardirqs_on_caller+0x114/0x13f [ 60.223447] [] ? trace_hardirqs_on+0xd/0xf [ 60.223454] [] vfs_fstatat+0x32/0x5d [ 60.223460] [] vfs_lstat+0x19/0x1b [ 60.223465] [] sys_newlstat+0x1a/0x38 [ 60.223471] [] ? trace_hardirqs_on_caller+0x114/0x13f [ 60.223477] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 60.223485] [] system_call_fastpath+0x16/0x1b -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/