From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [rfc patch v4.4-rt2] sched: fix up preempt lazy forward port Date: Fri, 22 Jan 2016 15:34:31 +0200 Message-ID: <56A22FE7.6070005@ti.com> References: <1453108103.4123.4.camel@gmail.com> <20160118201828.GE12309@linutronix.de> <1453170597.3740.7.camel@gmail.com> <20160121125405.GA11749@linutronix.de> <56A21F7D.9070101@ti.com> <56A22C49.5020401@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: Thomas Gleixner , LKML , linux-rt-users To: Sebastian Andrzej Siewior , Mike Galbraith Return-path: Received: from devils.ext.ti.com ([198.47.26.153]:40137 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753639AbcAVNeo (ORCPT ); Fri, 22 Jan 2016 08:34:44 -0500 In-Reply-To: <56A22C49.5020401@linutronix.de> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 01/22/2016 03:19 PM, Sebastian Andrzej Siewior wrote: > On 01/22/2016 01:24 PM, Grygorii Strashko wrote: >> I can see below backtrace during boot if i backport this change in K4.1-rt >> TI am437x-idk (UP) board. >> >> [ 0.204022] Switched to clocksource arm_global_timer >> [ 0.211982] ------------[ cut here ]------------ >> [ 0.212021] WARNING: CPU: 0 PID: 3 at kernel/softirq.c:894 __tasklet_action+0x150/0x17c() >> [ 0.212027] Modules linked in: >> [ 0.212041] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.15-rt11-00324-g52f8148-dirty #117 >> [ 0.212046] Hardware name: Generic AM43 (Flattened Device Tree) >> [ 0.212052] Backtrace: >> [ 0.212080] [] (dump_backtrace) from [] (show_stack+0x18/0x1c) >> [ 0.212085] r7:c0730a84 r6:0000037e r5:00000009 r4:00000000 >> [ 0.212112] [] (show_stack) from [] (dump_stack+0x20/0x28) >> [ 0.212124] [] (dump_stack) from [] (warn_slowpath_common+0x7c/0xb4) >> [ 0.212134] [] (warn_slowpath_common) from [] (warn_slowpath_null+0x24/0x2c) >> [ 0.212138] r8:000f4240 r7:00000000 r6:c0841238 r5:00000018 r4:00000006 >> [ 0.212156] [] (warn_slowpath_null) from [] (__tasklet_action+0x150/0x17c) >> [ 0.212165] [] (__tasklet_action) from [] (tasklet_action+0x30/0x38) >> [ 0.212169] r9:04208140 r8:c0862300 r7:000000c0 r6:c082d774 r5:00000018 r4:00000006 >> [ 0.212187] [] (tasklet_action) from [] (do_current_softirqs+0x190/0x258) >> [ 0.212197] [] (do_current_softirqs) from [] (run_ksoftirqd+0x30/0x58) >> [ 0.212201] r10:00000000 r9:00000000 r8:00000002 r7:c082d8f0 r6:00000001 r5:ee81f740 >> [ 0.212213] r4:ee874000 >> [ 0.212227] [] (run_ksoftirqd) from [] (smpboot_thread_fn+0x15c/0x278) >> [ 0.212242] [] (smpboot_thread_fn) from [] (kthread+0xcc/0xe4) >> [ 0.212246] r9:00000000 r8:00000000 r7:c0053384 r6:ee81f740 r5:ee81f780 r4:00000000 >> [ 0.212265] [] (kthread) from [] (ret_from_fork+0x14/0x2c) >> [ 0.212269] r7:00000000 r6:00000000 r5:c0050030 r4:ee81f780 >> [ 0.212279] ---[ end trace 0000000000000001 ]--- >> [ 0.212284] softirq: ================== c037d4c4 <---- t->func >> ^^ >> # grep c037d4c4 System.map >> c037d4c4 t kbd_bh > > Do you still see it with the missing lazy bits? I don't see where this > could come from. > yep. I've tried it with and without changing _TIF_WORK_MASK Seems It's triggered by Virtual terminal keyboard_tasklet -- regards, -grygorii