2018-12-14 09:55:05 +00:00
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 6 Dec 2018 09:52:20 +0100
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Subject: [PATCH] drm/i915: disable tracing on -RT
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2019-02-27 18:51:46 +00:00
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.25-rt16.tar.xz
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2018-12-14 09:55:05 +00:00
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Luca Abeni reported this:
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| BUG: scheduling while atomic: kworker/u8:2/15203/0x00000003
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| CPU: 1 PID: 15203 Comm: kworker/u8:2 Not tainted 4.19.1-rt3 #10
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| Call Trace:
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| rt_spin_lock+0x3f/0x50
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| gen6_read32+0x45/0x1d0 [i915]
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| g4x_get_vblank_counter+0x36/0x40 [i915]
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| trace_event_raw_event_i915_pipe_update_start+0x7d/0xf0 [i915]
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The tracing events use trace_i915_pipe_update_start() among other events
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use functions acquire spin locks. A few trace points use
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intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also
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might acquire a sleeping lock.
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Based on this I don't see any other way than disable trace points on RT.
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Cc: stable-rt@vger.kernel.org
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Reported-by: Luca Abeni <lucabe72@gmail.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/gpu/drm/i915/i915_trace.h | 4 ++++
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1 file changed, 4 insertions(+)
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--- a/drivers/gpu/drm/i915/i915_trace.h
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+++ b/drivers/gpu/drm/i915/i915_trace.h
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@@ -2,6 +2,10 @@
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#if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
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#define _I915_TRACE_H_
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+#ifdef CONFIG_PREEMPT_RT_BASE
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+#define NOTRACE
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+#endif
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+
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#include <linux/stringify.h>
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#include <linux/types.h>
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#include <linux/tracepoint.h>
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