| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Thu, 6 Dec 2018 09:52:20 +0100 |
| Subject: [PATCH] drm/i915: disable tracing on -RT |
| |
| 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> |
| --- |
| drivers/gpu/drm/i915/i915_trace.h | 4 ++++ |
| 1 file changed, 4 insertions(+) |
| |
| --- 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 |
| +#define NOTRACE |
| +#endif |
| + |
| #include <linux/stringify.h> |
| #include <linux/types.h> |
| #include <linux/tracepoint.h> |