6.6-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ 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 linux@roeck-us.net Suggested-by: "Steven Rostedt (Google)" rostedt@goodmis.org Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Tested-by: Guenter Roeck linux@roeck-us.net Link: https://lore.kernel.org/r/20250212103619.2560503-2-bigeasy@linutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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 4a1dc88ddbff9..2610a7d156da8 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -441,7 +441,7 @@ 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 } @@ -449,7 +449,7 @@ 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 } @@ -464,7 +464,7 @@ 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); @@ -472,7 +472,7 @@ 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);