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genirq/kexec: Do not take the bus lock of an interrupt chip on the crash path

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machine_kexec_mask_interrupts() calls irq_set_irqchip_state() for every
started interrupt. That function takes the bus lock of the chip and
desc->lock, and syncs the chip when it drops them. On the crash path
interrupts are off and the other CPUs are stopped, so a chip whose bus
transfer is completed by an interrupt never returns from the sync.

On RK3399 boards with an RK808 PMIC the RTC alarm interrupt belongs to
the regmap-irq chip of the RK808, which sits on I2C. rk808_irq_chip sets
init_ack_masked, so regmap_irq_sync_unlock() writes the ack register on
every unlock, and the I2C controller needs its own interrupt to finish
the transfer. A panic with a crash kernel loaded prints

  SMP: stopping secondary CPUs

and then nothing until the watchdog resets the board.

machine_kexec_mask_interrupts() takes neither lock for the other
operations on the descriptor. Move the search for the chip that
implements irq_set_irqchip_state() into __irq_set_irqchip_state(), which
takes no locks, and call it from machine_kexec_mask_interrupts().

Fixes: 78fd584cde ("arm64: kdump: implement machine_crash_shutdown()")
Suggested-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Igor Velkov <iav@iav.lv>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20261015-kexec-irq-bus-lock-v2-1-2af15f0757b6@iav.lv
This commit is contained in:
Igor Velkov 2026-10-15 21:51:50 +03:00 committed by Thomas Gleixner
parent c03c1a1450
commit 717862eac6
3 changed files with 26 additions and 20 deletions
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1
kernel/irq/internals.h
View File

@ -81,6 +81,7 @@ enum {
#include "settings.h"
extern int __irq_set_trigger(struct irq_desc *desc, unsigned long flags);
extern int __irq_set_irqchip_state(struct irq_desc *desc, enum irqchip_irq_state which, bool val);
extern void __disable_irq(struct irq_desc *desc);
extern void __enable_irq(struct irq_desc *desc);

2
kernel/irq/kexec.c
View File

@ -25,7 +25,7 @@ void machine_kexec_mask_interrupts(void)
* First try to remove the active state from an interrupt which is forwarded
* to a VM. If the interrupt is not forwarded, try to EOI the interrupt.
*/
check_eoi = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
check_eoi = __irq_set_irqchip_state(desc, IRQCHIP_STATE_ACTIVE, false);
}
if (check_eoi && chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))

43
kernel/irq/manage.c
View File

@ -2735,6 +2735,28 @@ int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which, bool *
}
EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
int __irq_set_irqchip_state(struct irq_desc *desc, enum irqchip_irq_state which, bool val)
{
struct irq_data *data = irq_desc_get_irq_data(desc);
struct irq_chip *chip;
do {
chip = irq_data_get_irq_chip(data);
if (WARN_ON_ONCE(!chip))
return -ENODEV;
if (chip->irq_set_irqchip_state)
break;
data = irqd_get_parent_data(data);
} while (data);
if (data)
return chip->irq_set_irqchip_state(data, which, val);
return -EINVAL;
}
/**
* irq_set_irqchip_state - set the state of a forwarded interrupt.
* @irq: Interrupt line that is forwarded to a VM
@ -2749,25 +2771,8 @@ EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
*/
int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, bool val)
{
scoped_irqdesc_get_and_buslock(irq, 0) {
struct irq_data *data = irq_desc_get_irq_data(scoped_irqdesc);
struct irq_chip *chip;
do {
chip = irq_data_get_irq_chip(data);
if (WARN_ON_ONCE(!chip))
return -ENODEV;
if (chip->irq_set_irqchip_state)
break;
data = irqd_get_parent_data(data);
} while (data);
if (data)
return chip->irq_set_irqchip_state(data, which, val);
}
scoped_irqdesc_get_and_buslock(irq, 0)
return __irq_set_irqchip_state(scoped_irqdesc, which, val);
return -EINVAL;
}
EXPORT_SYMBOL_GPL(irq_set_irqchip_state);