| Message ID | 20240613102818.4056866-5-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: PREEMPT_RT related fixups. | expand |
On 13/06/2024 11:20, Sebastian Andrzej Siewior wrote: > 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_intel_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@gmail.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > 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 49a5e6d9dc0d7..b15c999d91e68 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__ > > +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) > +#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..247e7d9448d70 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_ > > +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) > +#define NOTRACE > +#endif > + > #include <linux/stringify.h> > #include <linux/types.h> > #include <linux/tracepoint.h> If tracing experts said this is the way then it is fine by me. Acked-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com> Regards, Tvrtko
diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers/gpu/drm/i915/display/intel_display_trace.h index 49a5e6d9dc0d7..b15c999d91e68 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__ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#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..247e7d9448d70 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_ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#define NOTRACE +#endif + #include <linux/stringify.h> #include <linux/types.h> #include <linux/tracepoint.h>
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_intel_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@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- drivers/gpu/drm/i915/display/intel_display_trace.h | 4 ++++ drivers/gpu/drm/i915/i915_trace.h | 4 ++++ 2 files changed, 8 insertions(+)