On Wed, 10 Apr 2024 13:08:57 +0200 Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote: > On 2024-04-09 11:55:33 [-0400], Steven Rostedt wrote: > > I believe you need to do it in the .c file: > > > > Can you try something like this? > > > … > > ? > > I tried and nothing changed because the lowlevel config option isn't the > problem. What about I drop this and replace 4/10 from this series with > the patch below? After enabling all tracing I don't see any events in > events/i915. I don't see anything wrong with this approach. > > Sebastian > > --------------------->8---------------------------- > > From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Date: Thu, 6 Dec 2018 09:52:20 +0100 > Subject: [PATCH] drm/i915: Disable tracing points on PREEMPT_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 spinlock_t locks which are transformed into > sleeping locks on PREEMPT_RT. A few trace points use > intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also > might acquire a sleeping locks on PREEMPT_RT. > At the time the arguments are evaluated within trace point, preemption > is disabled and so the locks must not be acquired on PREEMPT_RT. > > Based on this I don't see any other way than disable trace points on > PREMPT_RT. > > Reported-by: Luca Abeni <lucabe72@xxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_display_trace.h | 4 ++++ > drivers/gpu/drm/i915/i915_trace.h | 4 ++++ > 2 files changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers/gpu/drm/i915/display/intel_display_trace.h > index 7862e7cefe027..e4608d855bfba 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_trace.h > +++ b/drivers/gpu/drm/i915/display/intel_display_trace.h > @@ -9,6 +9,10 @@ > #if !defined(__INTEL_DISPLAY_TRACE_H__) || defined(TRACE_HEADER_MULTI_READ) > #define __INTEL_DISPLAY_TRACE_H__ > > +#ifdef CONFIG_PREEMPT_RT Hmm, should these be: #if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) ? because it's not protected due to the TRACE_HEADER_MULTI_READ. -- Steve > +#define NOTRACE > +#endif > + > #include <linux/string_helpers.h> > #include <linux/types.h> > #include <linux/tracepoint.h> > diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h > index ce1cbee1b39dd..c54653cf72c95 100644 > --- a/drivers/gpu/drm/i915/i915_trace.h > +++ b/drivers/gpu/drm/i915/i915_trace.h > @@ -6,6 +6,10 @@ > #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>
