From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752366AbdBTKPi (ORCPT ); Mon, 20 Feb 2017 05:15:38 -0500 Received: from mout.gmx.net ([212.227.15.18]:62400 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751282AbdBTKPh (ORCPT ); Mon, 20 Feb 2017 05:15:37 -0500 Message-ID: <1487585723.8499.5.camel@gmx.de> Subject: [cgroups] suspicious rcu_dereference_check() usage! From: Mike Galbraith To: Tejun Heo Cc: LKML Date: Mon, 20 Feb 2017 11:15:23 +0100 Content-Type: text/plain; charset="us-ascii" X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:j/YNZU10eNRJz1KSyZdw+40iqEBA6HjiAHEEyx9x/SFGckmV5cK lgBgVISXR+iMpFBu4eZEfm4PwFCcp3WZGpRMls9kOVpN4VXuiLVeKUnOmGqN2CXYwVqIb9E Ra9JJxifxAwGgKHdHPBavqfb3JD2rfAuXbpomB2UHO2e3VT/qg+7/m1DeNwLEsGe2O1jwOq PZczOVzeLiJiXm1r2QzdA== X-UI-Out-Filterresults: notjunk:1;V01:K0:lWyhWRq2UYo=:GDB/n0N0YfPtEKqS0Fn9V/ Dl5mmKhDk7ecSoP7qQgac0yqhdrzbF21tSxEcNenh3acyAfkDE5sarmPkVnmjXKXAh6WpSTS/ ICaGgJJIjmxRRRFzmlWDziCWdqMKBC5YuR9M2cOP01uJyyCFKAFGdwDuk5XYBz19c413P1HKa puyzWZjfIW10JoQDsj1rl+3kEO3kCyLlDoglB/s3uJJyK3QLJoN9zMH0jgloWX1By76nEPaPP jvp3QfAeqN95As8Mq+qArbQv5mFBdPF0IMaEtN+s3bLGYCzHEoeMGaZIQsw4Lao3iy0y5TQ2t 7U0zQBi1lFvncPJQutg8v7eCpXVf5LwT46HrMXC/NcHx8vzsyJ4Eb2lf88444BCa0kWqHbHEu Hhw7fbaZ8J/0I+DOxdP7aOAmf418KabLi5nodlddY1ZZkLmYJETQzG4H+y7cD6GLalr4ybrhl BLu5IJ5Z4WPUyClMH6jxTzRSyxXDuDfIRA9YImmds901CKwl1WbmAfy+XnmxrlkZa35UtIvmP muOVnjqH30RasaUJ2KGxYiGNOAcYf+jolGKsn5lDiu5zV3Zgr9rGhZ6Z7n3b41ZrMdfjW9dX2 x4AybidQwnsty0gmLAeD1SdCSyFeh+EyM0Ixl9n3iAvCYxmNbXaVK5GSQI/ltSNyhECloZO55 rJ4Gw6HzU8rsHq2ppUSwWyrkBkGtFAvWcqvcvcFzlRqZYytrViFPciCyXEUKhRDKSDly+JrxR fFQYq3fcziR2kiBzKPC+dMf/yhiyhdx1swUOdoCKouTGnVR5G6rfnhMFUMx08/CY99uJ8s49b lUxdUEy Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Running LTP on master.today (v4.10) with a seriously bloated PREEMPT config inspired box to emit the below. [ 7160.458996] =============================== [ 7160.463195] [ INFO: suspicious RCU usage. ] [ 7160.467387] 4.10.0-default #100 Tainted: G E [ 7160.472808] ------------------------------- [ 7160.476999] ./include/linux/cgroup.h:435 suspicious rcu_dereference_check() usage! [ 7160.484576] [ 7160.484576] other info that might help us debug this: [ 7160.484576] [ 7160.492577] [ 7160.492577] rcu_scheduler_active = 2, debug_locks = 1 [ 7160.499113] 1 lock held by pids_task1/19308: [ 7160.503390] #0: (&cgroup_threadgroup_rwsem){+++++.}, at: [] _do_fork+0xf0/0x710 [ 7160.512450] [ 7160.512450] stack backtrace: [ 7160.516810] CPU: 5 PID: 19308 Comm: pids_task1 Tainted: G E 4.10.0-default #100 [ 7160.525239] Hardware name: IBM System x3550 M3 -[7944K3G]-/69Y5698 , BIOS -[D6E150AUS-1.10]- 12/15/2010 [ 7160.534965] Call Trace: [ 7160.537414] dump_stack+0x85/0xc9 [ 7160.540732] lockdep_rcu_suspicious+0xd5/0x110 [ 7160.545177] task_css.constprop.7+0x88/0x90 [ 7160.549357] pids_can_fork+0x132/0x160 [ 7160.553106] cgroup_can_fork+0x63/0xc0 [ 7160.556855] copy_process.part.30+0x17ef/0x21b0 [ 7160.561382] ? _do_fork+0xf0/0x710 [ 7160.564786] ? free_pages_and_swap_cache+0x9e/0xc0 [ 7160.569575] _do_fork+0xf0/0x710 [ 7160.572806] ? __this_cpu_preempt_check+0x13/0x20 [ 7160.577505] ? __percpu_counter_add+0x86/0xb0 [ 7160.581860] ? entry_SYSCALL_64_fastpath+0x5/0xc2 [ 7160.586562] ? do_syscall_64+0x2d/0x200 [ 7160.590395] SyS_clone+0x19/0x20 [ 7160.593623] do_syscall_64+0x6c/0x200 [ 7160.597283] entry_SYSCALL64_slow_path+0x25/0x25 [ 7160.601899] RIP: 0033:0x7fdaa3b881c4 [ 7160.605473] RSP: 002b:00007ffd21635d50 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 [ 7160.613036] RAX: ffffffffffffffda RBX: 0000000000004b6c RCX: 00007fdaa3b881c4 [ 7160.620162] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 [ 7160.627288] RBP: 00007ffd21635d90 R08: 0000000000000000 R09: 00007fdaa4052700 [ 7160.634414] R10: 00007fdaa40529d0 R11: 0000000000000246 R12: 00007ffd21635d50 [ 7160.641539] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000