From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753277AbcDXVO3 (ORCPT ); Sun, 24 Apr 2016 17:14:29 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:52362 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751170AbcDXVO1 (ORCPT ); Sun, 24 Apr 2016 17:14:27 -0400 Date: Sun, 24 Apr 2016 14:14:24 -0700 From: Guenter Roeck To: Boqun Feng Cc: "Paul E. McKenney" , Josh Triplett , Steven Rostedt , linux-kernel@vger.kernel.org Subject: next: suspicious RCU usage message since commit 'rcu: Remove superfluous versions of rcu_read_lock_sched_held()' Message-ID: <20160424211424.GA20388@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I see the following log message when running a qemu test for 'beagle' with omap2plus_defconfig. =============================== [ INFO: suspicious RCU usage. ] 4.6.0-rc4-next-20160422 #1 Not tainted ------------------------------- include/trace/events/power.h:328 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! no locks held by swapper/0/0. stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6.0-rc4-next-20160422 #1 Hardware name: Generic OMAP3-GP (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0xa8/0xe0) [] (dump_stack) from [] (pwrdm_set_next_pwrst+0xf8/0x1cc) [] (pwrdm_set_next_pwrst) from [] (omap3_enter_idle_bm+0x1b8/0x1e8) [] (omap3_enter_idle_bm) from [] (cpuidle_enter_state+0x84/0x408) [] (cpuidle_enter_state) from [] (cpu_startup_entry+0x1c8/0x3f0) [] (cpu_startup_entry) from [] (start_kernel+0x354/0x3cc) bisect points to commit 'rcu: Remove superfluous versions of rcu_read_lock_sched_held()'. Bisect log is attached. Thanks, Guenter --- # bad: [73442f7becf1b305c966ad37f5991d030f8bc025] Add linux-next specific files for 20160422 # good: [c3b46c73264b03000d1e18b22f5caf63332547c9] Linux 4.6-rc4 git bisect start 'HEAD' 'v4.6-rc4' # good: [f59d58f4c4c5d63b2f1768ab94465f9e98cd771d] Merge remote-tracking branch 'l2-mtd/master' git bisect good f59d58f4c4c5d63b2f1768ab94465f9e98cd771d # good: [ee634dd861741fa3112263c5fcd562e7953a8f3e] Merge remote-tracking branch 'tip/auto-latest' git bisect good ee634dd861741fa3112263c5fcd562e7953a8f3e # bad: [56ce28694cb53fb5609feca2735736583a35d5d1] Merge remote-tracking branch 'staging/staging-next' git bisect bad 56ce28694cb53fb5609feca2735736583a35d5d1 # good: [9acc4500b44723d12bec63519038ef820479eaad] staging/lustre/llite: rename struct ccc_thread_info to vvp_thread_info git bisect good 9acc4500b44723d12bec63519038ef820479eaad # bad: [95585a7b8c5f8eac40402378bc7482376f17a3ff] Merge remote-tracking branch 'driver-core/driver-core-next' git bisect bad 95585a7b8c5f8eac40402378bc7482376f17a3ff # bad: [3052fd5d2b38b26deaa195aec34f18bacccdf40c] torture: Add starvation events to error summary git bisect bad 3052fd5d2b38b26deaa195aec34f18bacccdf40c # good: [a54062c0d95921d4fb0edc8d268021bf387e6c75] rcutorture: Add boot-time adjustment of leaf fanout git bisect good a54062c0d95921d4fb0edc8d268021bf387e6c75 # bad: [dcd36d01fb3f99d1d5df01714f6ccbe3fbbaf81f] Merge branches 'doc.2016.04.19a', 'exp.2016.03.31d', 'fixes.2016.03.31d' and 'torture.2016.04.21a' into HEAD git bisect bad dcd36d01fb3f99d1d5df01714f6ccbe3fbbaf81f # good: [3b5f668e715bc19610ad967ef97a7e8c55a186ec] rcu: Overlap wakeups with next expedited grace period git bisect good 3b5f668e715bc19610ad967ef97a7e8c55a186ec # good: [5413e24c943da33306047fc091fa34fa4f261b3b] documentation: Sharpen up the no-readers quick quiz git bisect good 5413e24c943da33306047fc091fa34fa4f261b3b # bad: [293e2421fe25839500207eda123cc4475f8d17b8] rcu: Remove superfluous versions of rcu_read_lock_sched_held() git bisect bad 293e2421fe25839500207eda123cc4475f8d17b8 # good: [fcfd0a237bfcf0c314005007e9d76e55a25e2bad] rcu: Make FQS schedule advance only if FQS happened git bisect good fcfd0a237bfcf0c314005007e9d76e55a25e2bad # good: [8c7c4829a81c1838f18c12ce5a3a5c29a08bf0a8] rcu: Awaken grace-period kthread if too long since FQS git bisect good 8c7c4829a81c1838f18c12ce5a3a5c29a08bf0a8 # first bad commit: [293e2421fe25839500207eda123cc4475f8d17b8] rcu: Remove superfluous versions of rcu_read_lock_sched_held()