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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch b/debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch new file mode 100644 index 0000000000..f29f29bdfe --- /dev/null +++ b/debian/patches-rt/0006-drm-i915-Disable-tracing-points-on-PREEMPT_RT.patch @@ -0,0 +1,45 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Thu, 6 Dec 2018 09:52:20 +0100 +Subject: [PATCH 06/10] drm/i915: Disable tracing points on PREEMPT_RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +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@gmail.com> +Cc: Steven Rostedt <rostedt@goodmis.org> +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 +@@ -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> |