Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755995Ab0DWTnC (ORCPT ); Fri, 23 Apr 2010 15:43:02 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:42349 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755197Ab0DWTm7 (ORCPT ); Fri, 23 Apr 2010 15:42:59 -0400 Date: Fri, 23 Apr 2010 12:42:55 -0700 From: "Paul E. McKenney" To: Miles Lane 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 Subject: Re: [PATCH] RCU: don't turn off lockdep when find suspicious rcu_dereference_check() usage Message-ID: <20100423194255.GE2589@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7064 Lines: 130 On Fri, Apr 23, 2010 at 08:50:59AM -0400, Miles Lane wrote: > 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? Hello, Miles, I am posting my set as replies to this message. There are a couple of KVM fixes that are going up via Avi's tree, and a number of networking fixes that are going up via Dave Miller's tree -- a number of these are against quickly changing code, so it didn't make sense for me to keep them separately. I believe that the two splats below are addressed by this patch set carried in the networking tree: https://patchwork.kernel.org/patch/90754/ Thanx, Paul > 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/