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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch b/debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch new file mode 100644 index 000000000..0f030b42f --- /dev/null +++ b/debian/patches-rt/drm-i915-guc-Consider-also-RCU-depth-in-busy-loop.patch @@ -0,0 +1,29 @@ +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Tue, 3 Oct 2023 21:37:21 +0200 +Subject: [PATCH] drm/i915/guc: Consider also RCU depth in busy loop. +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +intel_guc_send_busy_loop() looks at in_atomic() and irqs_disabled() to +decide if it should busy-spin while waiting or if it may sleep. +Both checks will report false on PREEMPT_RT if sleeping spinlocks are +acquired leading to RCU splats while the function sleeps. + +Check also if RCU has been disabled. + +Reported-by: "John B. Wyatt IV" <jwyatt@redhat.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/gpu/drm/i915/gt/uc/intel_guc.h | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h ++++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h +@@ -317,7 +317,7 @@ static inline int intel_guc_send_busy_lo + { + int err; + unsigned int sleep_period_ms = 1; +- bool not_atomic = !in_atomic() && !irqs_disabled(); ++ bool not_atomic = !in_atomic() && !irqs_disabled() && !rcu_preempt_depth(); + + /* + * FIXME: Have caller pass in if we are in an atomic context to avoid |