]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
lockdep: Don't disable interrupts on RT in disable_irq_nosync_lockdep.*()
authorSebastian Andrzej Siewior <bigeasy@linutronix.de>
Wed, 12 Feb 2025 10:36:18 +0000 (11:36 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 10 Apr 2025 12:39:12 +0000 (14:39 +0200)
commit345957c1cfb85fbbe6307f8862b62ca8c37ae683
tree7685d20cbf3ce8fd0f29bdfe14206c7fd14d08ae
parentc3a4c91a409e60db66f881c075743b39a86d2bdb
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 <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