From 3a96b835f82ee5ecf11b286e81e2946fa45253c3 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 12 Feb 2025 11:36:18 +0100 Subject: [PATCH] lockdep: Don't disable interrupts on RT in disable_irq_nosync_lockdep.*() [ Upstream commit 87886b32d669abc11c7be95ef44099215e4f5788 ] disable_irq_nosync_lockdep() disables interrupts with lockdep enabled to avoid false positive reports by lockdep that a certain lock has not been acquired with disabled interrupts. The user of this macros expects that a lock can be acquried without disabling interrupts because the IRQ line triggering the interrupt is disabled. This triggers a warning on PREEMPT_RT because after disable_irq_nosync_lockdep.*() the following spinlock_t now is acquired with disabled interrupts. On PREEMPT_RT there is no difference between spin_lock() and spin_lock_irq() so avoiding disabling interrupts in this case works for the two remaining callers as of today. Don't disable interrupts on PREEMPT_RT in disable_irq_nosync_lockdep.*(). Closes: https://lore.kernel.org/760e34f9-6034-40e0-82a5-ee9becd24438@roeck-us.net Fixes: e8106b941ceab ("[PATCH] lockdep: core, add enable/disable_irq_irqsave/irqrestore() APIs") Reported-by: Guenter Roeck Suggested-by: "Steven Rostedt (Google)" Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Tested-by: Guenter Roeck Link: https://lore.kernel.org/r/20250212103619.2560503-2-bigeasy@linutronix.de Signed-off-by: Sasha Levin --- include/linux/interrupt.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 1f22a30c09637..976bca44bae0c 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -408,7 +408,7 @@ irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec, static inline void disable_irq_nosync_lockdep(unsigned int irq) { disable_irq_nosync(irq); -#ifdef CONFIG_LOCKDEP +#if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) local_irq_disable(); #endif } @@ -416,7 +416,7 @@ static inline void disable_irq_nosync_lockdep(unsigned int irq) static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags) { disable_irq_nosync(irq); -#ifdef CONFIG_LOCKDEP +#if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) local_irq_save(*flags); #endif } @@ -431,7 +431,7 @@ static inline void disable_irq_lockdep(unsigned int irq) static inline void enable_irq_lockdep(unsigned int irq) { -#ifdef CONFIG_LOCKDEP +#if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) local_irq_enable(); #endif enable_irq(irq); @@ -439,7 +439,7 @@ static inline void enable_irq_lockdep(unsigned int irq) static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags) { -#ifdef CONFIG_LOCKDEP +#if defined(CONFIG_LOCKDEP) && !defined(CONFIG_PREEMPT_RT) local_irq_restore(*flags); #endif enable_irq(irq); -- 2.47.3