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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Carsten Emde <C.Emde@osadl.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	John Kacur <jkacur@redhat.com>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Julia Cartwright <julia@ni.com>,
	Daniel Wagner <daniel.wagner@siemens.com>,
	tom.zanussi@linux.intel.com, stable-rt@vger.kernel.org,
	Luca Abeni <lucabe72@gmail.com>
Subject: [PATCH RT 10/13] drm/i915: disable tracing on -RT
Date: Mon, 07 Jan 2019 14:53:02 -0500	[thread overview]
Message-ID: <20190107195333.594740538@goodmis.org> (raw)
In-Reply-To: 20190107195252.599921907@goodmis.org

4.14.87-rt50-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

[ Upstream commit 05cebb309b156646e61b898e92acc8e46c47ba75 ]

Luca Abeni reported this:
| BUG: scheduling while atomic: kworker/u8:2/15203/0x00000003
| CPU: 1 PID: 15203 Comm: kworker/u8:2 Not tainted 4.19.1-rt3 #10
| Call Trace:
|  rt_spin_lock+0x3f/0x50
|  gen6_read32+0x45/0x1d0 [i915]
|  g4x_get_vblank_counter+0x36/0x40 [i915]
|  trace_event_raw_event_i915_pipe_update_start+0x7d/0xf0 [i915]

The tracing events use trace_i915_pipe_update_start() among other events
use functions acquire spin locks. A few trace points use
intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also
might acquire a sleeping lock.

Based on this I don't see any other way than disable trace points on RT.

Cc: stable-rt@vger.kernel.org
Reported-by: Luca Abeni <lucabe72@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 drivers/gpu/drm/i915/i915_trace.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
index ef72da74b87f..adf0974415bc 100644
--- a/drivers/gpu/drm/i915/i915_trace.h
+++ b/drivers/gpu/drm/i915/i915_trace.h
@@ -2,6 +2,10 @@
 #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
 #define _I915_TRACE_H_
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+#define NOTRACE
+#endif
+
 #include <linux/stringify.h>
 #include <linux/types.h>
 #include <linux/tracepoint.h>
-- 
2.19.2

  parent reply	other threads:[~2019-01-07 19:53 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-07 19:52 [PATCH RT 00/13] Linux 4.14.87-rt50-rc1 Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 01/13] work-simple: drop a shit statement in SWORK_EVENT_PENDING Steven Rostedt
2019-01-08  3:06   ` Sergey Senozhatsky
2019-01-08  3:26     ` Steven Rostedt
2019-01-08  4:47       ` Sergey Senozhatsky
2019-01-08  9:00         ` Sebastian Andrzej Siewior
2019-01-07 19:52 ` [PATCH RT 02/13] kthread: convert worker lock to raw spinlock Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 03/13] mm/kasan: make quarantine_lock a raw_spinlock_t Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 05/13] sched/migrate_disable: Add export_symbol_gpl for __migrate_disabled Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 06/13] pinctrl: bcm2835: Use raw spinlock for RT compatibility Steven Rostedt
2019-01-07 19:52 ` [PATCH RT 07/13] rcu: make RCU_BOOST default on RT without EXPERT Steven Rostedt
2019-01-07 19:53 ` [PATCH RT 08/13] x86/fpu: Disable preemption around local_bh_disable() Steven Rostedt
2019-01-07 19:53 ` [PATCH RT 09/13] hrtimer: move state change before hrtimer_cancel in do_nanosleep() Steven Rostedt
2019-01-07 19:53 ` Steven Rostedt [this message]
2019-01-07 20:10   ` [PATCH RT 10/13] drm/i915: disable tracing on -RT Sebastian Andrzej Siewior
2019-01-07 19:53 ` [PATCH RT 11/13] x86/mm/pat: disable preemption __split_large_page() after spin_lock() Steven Rostedt
2019-01-07 19:53 ` [PATCH RT 13/13] Linux 4.14.87-rt50-rc1 Steven Rostedt

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