Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753587Ab3IKN01 (ORCPT ); Wed, 11 Sep 2013 09:26:27 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:5901 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752170Ab3IKN0Z (ORCPT ); Wed, 11 Sep 2013 09:26:25 -0400 X-Authority-Analysis: v=2.0 cv=R/aB6KtX c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=wRe-vSF1Ob0A:10 a=5SG0PmZfjMsA:10 a=kj9zAlcOel0A:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=kSsn7R9otuIA:10 a=oExj5NFNAAAA:8 a=97CWKrAFWwtIgTIf3yEA:9 a=CjuIK1q_8ugA:10 a=r0HesoeFUbUA:10 a=i1XarcQiEwcA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Date: Wed, 11 Sep 2013 09:26:23 -0400 From: Steven Rostedt To: "Luis Claudio R. Goncalves" Cc: linux-rt-users , Thomas Gleixner , Sebastian Andrzej Siewior , Clark Williams , Mario Kleiner , Dave Airlie , LKML Subject: Re: BUG: sleeping function called from invalid context on 3.10.10-rt7 Message-ID: <20130911092623.42efd930@gandalf.local.home> In-Reply-To: <20130911102809.GA31663@uudg.org> References: <20130911102809.GA31663@uudg.org> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.20; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8400 Lines: 164 On Wed, 11 Sep 2013 07:28:09 -0300 "Luis Claudio R. Goncalves" wrote: > Hello, > > I saw two different occurrences of "BUG: sleeping function called from > invalid context" happening on 3.10.10-rt7. The first one happened on > drm_vblank_get() -> i915_get_vblank_timestamp() and was flooding dmesg > after Xorg started. I silenced that with a hackish patch, just for fun, and > found a second problem, this time on tty_ldisc_reinit(). > > The logs: > > [ 23.973991] BUG: sleeping function called from invalid context at /home/lclaudio/SANDBOX/mrg-rt-v2-devel/kernel/rtmutex.c:659 > [ 23.973992] in_atomic(): 1, irqs_disabled(): 0, pid: 517, name: Xorg > [ 23.973993] 2 locks held by Xorg/517: > [ 23.973993] #0: > [ 23.973994] ( > [ 23.973994] &dev->vbl_lock > [ 23.973995] ){......} > [ 23.973995] , at: > [ 23.974007] [] drm_vblank_get+0x30/0x2b0 [drm] > [ 23.974008] #1: > [ 23.974008] ( > [ 23.974008] &dev->vblank_time_lock > [ 23.974008] ){......} > [ 23.974009] , at: > [ 23.974013] [] drm_vblank_get+0xb1/0x2b0 [drm] > [ 23.974013] Preemption disabled at: > [ 23.974021] [] i915_get_vblank_timestamp+0x45/0xa0 [i915] > [ 23.974023] CPU: 3 PID: 517 Comm: Xorg Not tainted 3.10.10-rt7+ #5 > [ 23.974024] Hardware name: Hewlett-Packard p7-1512/2ADA, BIOS 8.15 02/05/2013 > [ 23.974024] 0000000000070008 > [ 23.974025] ffff88017a08bae0 > [ 23.974025] ffffffff8164b790 > [ 23.974025] ffff88017a08baf8 > [ 23.974026] ffffffff8107e62f > [ 23.974026] ffff880179840040 > [ 23.974026] ffff88017a08bb18 > [ 23.974027] ffffffff81651ac4 > [ 23.974027] 0000000000000002 > [ 23.974027] ffff880179840000 > [ 23.974028] ffff88017a08bb48 > [ 23.974028] ffffffffa0084e67 > [ 23.974028] Call Trace: > [ 23.974033] [] dump_stack+0x19/0x1b > [ 23.974035] [] __might_sleep+0xff/0x170 > [ 23.974037] [] rt_spin_lock+0x24/0x60 > [ 23.974043] [] i915_read32+0x27/0x170 [i915] > [ 23.974048] [] i915_pipe_enabled+0x31/0x40 [i915] > [ 23.974054] [] i915_get_crtc_scanoutpos+0x3e/0x1b0 [i915] > [ 23.974056] [] ? sched_clock_cpu+0xb5/0x100 > [ 23.974062] [] drm_calc_vbltimestamp_from_scanoutpos+0xf4/0x430 [drm] > [ 23.974068] [] i915_get_vblank_timestamp+0x45/0xa0 [i915] > [ 23.974073] [] drm_get_last_vbltimestamp+0x48/0x70 [drm] > [ 23.974078] [] drm_vblank_get+0x185/0x2b0 [drm] > [ 23.974079] [] ? sched_clock_cpu+0xb5/0x100 > [ 23.974085] [] drm_wait_vblank+0x83/0x5d0 [drm] > [ 23.974086] [] ? sched_clock_cpu+0xb5/0x100 > [ 23.974088] [] ? __lock_acquire.isra.31+0x273/0xa70 > [ 23.974093] [] drm_ioctl+0x552/0x6a0 [drm] > [ 23.974096] [] ? avc_has_perm_flags+0x126/0x1c0 > [ 23.974098] [] ? avc_has_perm_flags+0x28/0x1c0 > [ 23.974099] [] ? put_lock_stats.isra.23+0xe/0x40 > [ 23.974101] [] do_vfs_ioctl+0x325/0x5b0 > [ 23.974103] [] ? file_has_perm+0x8e/0xa0 > [ 23.974105] [] SyS_ioctl+0x81/0xa0 > [ 23.974107] [] tracesys+0xdd/0xe2 > > > and > > > [ 25.423675] BUG: sleeping function called from invalid context at /home/lclaudio/SANDBOX/mrg-rt-v2-devel/kernel/rtmutex.c:659 > [ 25.423676] in_atomic(): 1, irqs_disabled(): 1, pid: 188, name: plymouthd > [ 25.423676] 3 locks held by plymouthd/188: > [ 25.423682] #0: (&tty->legacy_mutex){......}, at: [] tty_lock_nested+0x40/0x90 > [ 25.423686] #1: (&tty->ldisc_mutex){......}, at: [] tty_ldisc_hangup+0x152/0x300 > [ 25.423688] #2: (tty_ldisc_lock){......}, at: [] tty_ldisc_reinit+0x72/0x130 > [ 25.423689] Preemption disabled at:[] tty_ldisc_reinit+0x72/0x130 > [ 25.423691] CPU: 2 PID: 188 Comm: plymouthd Not tainted 3.10.10-rt7+ #6 > [ 25.423692] Hardware name: Hewlett-Packard p7-1512/2ADA, BIOS 8.15 02/05/2013 > [ 25.423694] 005ff00000000000 ffff8801788ada68 ffffffff8164b790 ffff8801788ada80 > [ 25.423695] ffffffff8107e62f ffff8801991ce1a0 ffff8801788adaa0 ffffffff81651ac4 > [ 25.423696] 0000000000000000 ffffea0005e26680 ffff8801788adaf8 ffffffff81130984 > [ 25.423696] Call Trace: > [ 25.423700] [] dump_stack+0x19/0x1b > [ 25.423702] [] __might_sleep+0xff/0x170 > [ 25.423704] [] rt_spin_lock+0x24/0x60 > [ 25.423707] [] free_hot_cold_page+0xb4/0x3c0 > [ 25.423710] [] ?unfreeze_partials.isra.42+0x229/0x2b0 > [ 25.423711] [] __free_pages+0x47/0x70 > [ 25.423713] [] __free_memcg_kmem_pages+0x22/0x50 > [ 25.423714] [] __free_slab+0xe8/0x1e0 > [ 25.423716] [] free_delayed+0x34/0x50 > [ 25.423717] [] __slab_free+0x273/0x36b > [ 25.423719] [] ? get_lock_stats+0x19/0x60 > [ 25.423721] [] ? put_lock_stats.isra.23+0xe/0x40 > [ 25.423722] [] kfree+0x1c4/0x210 > [ 25.423724] [] ? tty_ldisc_reinit+0xa5/0x130 > [ 25.423725] [] tty_ldisc_reinit+0xa5/0x130 > [ 25.423726] [] tty_ldisc_hangup+0x16f/0x300 > [ 25.423728] [] ? get_parent_ip+0xd/0x50 > [ 25.423731] [] ? unpin_current_cpu+0x16/0x70 > [ 25.423732] [] __tty_hangup+0x346/0x460 > [ 25.423733] [] tty_vhangup+0x10/0x20 > [ 25.423735] [] pty_close+0x131/0x180 > [ 25.423736] [] tty_release+0x11d/0x5f0 > [ 25.423737] [] ? get_lock_stats+0x19/0x60 > [ 25.423747] [] ? native_sched_clock+0x24/0x80 > [ 25.423749] [] ? sched_clock_cpu+0xb5/0x100 > [ 25.423750] [] ? get_lock_stats+0x19/0x60 > [ 25.423752] [] __fput+0xf5/0x250 > [ 25.423762] [] ____fput+0xe/0x10 > [ 25.423764] [] task_work_run+0xac/0xe0 > [ 25.423765] [] do_notify_resume+0x91/0xf0 > [ 25.423767] [] int_signal+0x12/0x17 > > > About the hackish patch I used to silence the constant i915 complaints, > even though the comments on drm_calc_vbltimestamp_from_scanoutpos() state > the preempt_disable is there for a reason, I removed it for the RT case. I > really wanted to confirm if there was anything else after that complaint. The funny part is, there's a comment there that shows that this was done even for "PREEMPT_RT". Unfortunately, the call to "get_scanout_position()" can call functions that use the rt-mutex "sleeping spin locks" and it breaks there. I guess we need to ask the authors of the mainline patch exactly why that preempt_disable() is needed? -- Steve > > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c > index f92da0a..bd2e8e2 100644 > --- a/drivers/gpu/drm/drm_irq.c > +++ b/drivers/gpu/drm/drm_irq.c > @@ -631,7 +631,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, > /* Disable preemption to make it very likely to > * succeed in the first iteration even on PREEMPT_RT kernel. > */ > - preempt_disable(); > + preempt_disable_nort(); > > /* Get system timestamp before query. */ > stime = ktime_get(); > @@ -644,7 +644,7 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, > if (!drm_timestamp_monotonic) > mono_time_offset = ktime_get_monotonic_offset(); > > - preempt_enable(); > + preempt_enable_nort(); > > /* Return as no-op if scanout query unsupported or failed. */ > if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { > -- 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/