From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: 2.6.35-rc2-git1 - net/mac80211/sta_info.c:125 invoked rcu_dereference_check() without protection! Date: Mon, 7 Jun 2010 16:59:42 -0700 Message-ID: <20100607235941.GD2387@linux.vnet.ibm.com> References: Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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 , Johannes Berg To: Miles Lane Return-path: Received: from e9.ny.us.ibm.com ([32.97.182.139]:58504 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750834Ab0FGX7p (ORCPT ); Mon, 7 Jun 2010 19:59:45 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Jun 07, 2010 at 02:25:44PM -0400, Miles Lane wrote: > [ 43.478812] [ INFO: suspicious rcu_dereference_check() usage. ] > [ 43.478815] --------------------------------------------------- > [ 43.478820] net/mac80211/sta_info.c:125 invoked > rcu_dereference_check() without protection! > [ 43.478824] > [ 43.478824] other info that might help us debug this: > [ 43.478826] > [ 43.478829] > [ 43.478830] rcu_scheduler_active = 1, debug_locks = 1 > [ 43.478834] no locks held by NetworkManager/4017. Hmmm... Johannes's update has been merged, and it requires that callers either be in an RCU read-side critical section or hold either the ->sta_lock or the ->sta_mtx, and this thread does none of this. Johannes, any thoughts? Thanx, Paul > [ 43.478837] stack backtrace: > [ 43.478842] Pid: 4017, comm: NetworkManager Not tainted 2.6.35-rc2-git1 #8 > [ 43.478846] Call Trace: > [ 43.478849] [] lockdep_rcu_dereference+0x9d/0xa5 > [ 43.478876] [] sta_info_get_bss+0x71/0x12d [mac80211] > [ 43.478889] [] ieee80211_find_sta+0x15/0x2f [mac80211] > [ 43.478902] [] iwlagn_tx_queue_reclaim+0xe7/0x1bb [iwlagn] > [ 43.478909] [] ? mark_lock+0x2d/0x262 > [ 43.478920] [] iwlagn_rx_reply_tx+0x4cd/0x58a [iwlagn] > [ 43.478928] [] ? is_swiotlb_buffer+0x2e/0x3b > [ 43.478937] [] iwl_rx_handle+0x161/0x2bf [iwlagn] > [ 43.478946] [] iwl_irq_tasklet+0x2eb/0x408 [iwlagn] > [ 43.478953] [] tasklet_action+0xa7/0x10f > [ 43.478960] [] __do_softirq+0x148/0x25a > [ 43.478966] [] call_softirq+0x1c/0x28 > [ 43.478972] [] do_softirq+0x38/0x80 > [ 43.478977] [] irq_exit+0x45/0x94 > [ 43.478983] [] do_IRQ+0xad/0xc4 > [ 43.478989] [] ret_from_intr+0x0/0xf > [ 43.478993]