Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757558Ab0HDK4N (ORCPT ); Wed, 4 Aug 2010 06:56:13 -0400 Received: from moutng.kundenserver.de ([212.227.17.8]:49494 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755789Ab0HDK4M (ORCPT ); Wed, 4 Aug 2010 06:56:12 -0400 Message-ID: <4C594740.1090608@vlnb.net> Date: Wed, 04 Aug 2010 14:56:00 +0400 From: Vladislav Bolkhovitin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.10) Gecko/20100527 Thunderbird/3.0.5 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: 2.6.35: suspicious rcu_dereference_check() usage Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Provags-ID: V02:K0:LnO7PupMlFIUc7gel5kYr+QrDky++vK6P3PnAzwhZ3x OcA15uqa6CMiNgGHEtNcrep7flj4wyXGZu2mYFyCczpJuqptwn P4yGuiMr6yv5sH/XkQgiOmzE/pqiYuUeNThq+hJp3921uFQbVp kTCAbuJyMBunOcrA0j4uh9R+0W10qjMMhXTkOltXPLn7PT9ekf UP5uREPBwSjp0AWYxa8RQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4314 Lines: 41 Hello, Today I gave a first try to 2.6.35 and it immediately produced: Aug 4 15:12:09 tgt kernel: [ 183.799040] =================================================== Aug 4 15:12:09 tgt kernel: [ 183.799158] [ INFO: suspicious rcu_dereference_check() usage. ] Aug 4 15:12:09 tgt kernel: [ 183.799158] --------------------------------------------------- Aug 4 15:12:09 tgt kernel: [ 183.799158] kernel/exit.c:1387 invoked rcu_dereference_check() without protection! Aug 4 15:12:09 tgt kernel: [ 183.799158] Aug 4 15:12:09 tgt kernel: [ 183.799158] other info that might help us debug this: Aug 4 15:12:09 tgt kernel: [ 183.799158] Aug 4 15:12:09 tgt kernel: [ 183.799158] Aug 4 15:12:09 tgt kernel: [ 183.799158] rcu_scheduler_active = 1, debug_locks = 1 Aug 4 15:12:09 tgt kernel: [ 183.799158] 2 locks held by mc/3751: Aug 4 15:12:09 tgt kernel: [ 183.799158] #0: (tasklist_lock){.+.+..}, at: [<7813d277>] do_wait+0xa1/0x24f Aug 4 15:12:09 tgt kernel: [ 183.799158] #1: (&(&sighand->siglock)->rlock){-.....}, at: [<7813c6eb>] wait_consider_task+0xdd/0xbc8 Aug 4 15:12:09 tgt kernel: [ 183.799158] Aug 4 15:12:09 tgt kernel: [ 183.799158] stack backtrace: Aug 4 15:12:09 tgt kernel: [ 183.799158] Pid: 3751, comm: mc Not tainted 2.6.35-scst-dbg #3 Aug 4 15:12:09 tgt kernel: [ 183.799158] Call Trace: Aug 4 15:12:09 tgt kernel: [ 183.799158] [<784660a3>] ? printk+0x2d/0x32 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78165d6e>] lockdep_rcu_dereference+0x8e/0x96 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813caa3>] wait_consider_task+0x495/0xbc8 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7846c809>] ? sub_preempt_count+0x9/0xad Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78164056>] ? put_lock_stats+0xd/0x28 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d277>] ? do_wait+0xa1/0x24f Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78469218>] ? _raw_read_lock+0x6b/0x72 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d2ca>] do_wait+0xf4/0x24f Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d48d>] sys_wait4+0x68/0xb2 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813afbd>] ? child_wait_callback+0x0/0x73 Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d503>] sys_waitpid+0x2c/0x2e Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78102d13>] sysenter_do_call+0x12/0x32 I guess, it was just after I started mc. Vlad -- 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/