The following commit has been merged into the locking/core branch of tip:
Commit-ID: 87886b32d669abc11c7be95ef44099215e4f5788
Gitweb: https://git.kernel.org/tip/87886b32d669abc11c7be95ef44099215e4f5788
Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Wed, 12 Feb 2025 11:36:18 +01:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 14 Mar 2025 21:13:20 +01:00
lockdep: Don't disable interrupts on RT in disable_irq_nosync_lockdep.*()
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@xxxxxxxxxxxx
Fixes: e8106b941ceab ("[PATCH] lockdep: core, add enable/disable_irq_irqsave/irqrestore() APIs")
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Suggested-by: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250212103619.2560503-2-bigeasy@xxxxxxxxxxxxx
---
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 8cd9327..a1b1be9 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -448,7 +448,7 @@ 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
}
@@ -456,7 +456,7 @@ 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
}
@@ -471,7 +471,7 @@ 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);
@@ -479,7 +479,7 @@ 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);
|