5.4-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
commit 94cff94634e506a4a44684bee1875d2dbf782722 upstream.
On x86 during boot, clockevent_i8253_disable() can be invoked via x86_late_time_init -> hpet_time_init() -> pit_timer_init() which happens with enabled interrupts.
If some of the old i8253 hardware is actually used then lockdep will notice that i8253_lock is used in hard interrupt context. This causes lockdep to complain because it observed the lock being acquired with interrupts enabled and in hard interrupt context.
Make clockevent_i8253_disable() acquire the lock with raw_spinlock_irqsave() to cure this.
[ tglx: Massage change log and use guard() ]
Fixes: c8c4076723dac ("x86/timer: Skip PIT initialization on modern chipsets") Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20250404133116.p-XRWJXf@linutronix.de Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/clocksource/i8253.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/clocksource/i8253.c +++ b/drivers/clocksource/i8253.c @@ -103,7 +103,9 @@ int __init clocksource_i8253_init(void) #ifdef CONFIG_CLKEVT_I8253 void clockevent_i8253_disable(void) { - raw_spin_lock(&i8253_lock); + unsigned long flags; + + raw_spin_lock_irqsave(&i8253_lock, flags);
/* * Writing the MODE register should stop the counter, according to @@ -133,7 +135,7 @@ void clockevent_i8253_disable(void)
outb_p(0x30, PIT_MODE);
- raw_spin_unlock(&i8253_lock); + raw_spin_unlock_irqrestore(&i8253_lock, flags); }
static int pit_shutdown(struct clock_event_device *evt)