Messages in this thread Patch in this message | | | From | Ben Luo <> | Subject | [PATCH v5 1/3] genirq: enhance error recovery code in free irq | Date | Fri, 30 Aug 2019 16:41:27 +0800 |
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__free_irq()/__free_percpu_irq() need to return if called from IRQ context because the interrupt handler loop runs with desc->lock dropped and dev_id can be subject to load and store tearing. Also move WARNs out of lock region and print out dev_id to help debugging.
Signed-off-by: Ben Luo <luoben@linux.alibaba.com> --- kernel/irq/manage.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index e8f7f17..10ec3e9 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1690,7 +1690,10 @@ static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id) struct irqaction *action, **action_ptr; unsigned long flags; - WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq); + if (WARN(in_interrupt(), + "Trying to free IRQ %d (dev_id %p) from IRQ context!\n", + irq, dev_id)) + return NULL; mutex_lock(&desc->request_mutex); chip_bus_lock(desc); @@ -1705,10 +1708,11 @@ static struct irqaction *__free_irq(struct irq_desc *desc, void *dev_id) action = *action_ptr; if (!action) { - WARN(1, "Trying to free already-free IRQ %d\n", irq); raw_spin_unlock_irqrestore(&desc->lock, flags); chip_bus_sync_unlock(desc); mutex_unlock(&desc->request_mutex); + WARN(1, "Trying to free already-free IRQ %d (dev_id %p)\n", + irq, dev_id); return NULL; } @@ -2286,7 +2290,10 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_ struct irqaction *action; unsigned long flags; - WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq); + if (WARN(in_interrupt(), + "Trying to free IRQ %d (dev_id %p) from IRQ context!\n", + irq, dev_id)) + return NULL; if (!desc) return NULL; @@ -2295,14 +2302,17 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_ action = desc->action; if (!action || action->percpu_dev_id != dev_id) { - WARN(1, "Trying to free already-free IRQ %d\n", irq); - goto bad; + raw_spin_unlock_irqrestore(&desc->lock, flags); + WARN(1, "Trying to free already-free IRQ (dev_id %p) %d\n", + dev_id, irq); + return NULL; } if (!cpumask_empty(desc->percpu_enabled)) { - WARN(1, "percpu IRQ %d still enabled on CPU%d!\n", - irq, cpumask_first(desc->percpu_enabled)); - goto bad; + raw_spin_unlock_irqrestore(&desc->lock, flags); + WARN(1, "percpu IRQ %d (dev_id %p) still enabled on CPU%d!\n", + irq, dev_id, cpumask_first(desc->percpu_enabled)); + return NULL; } /* Found it - now remove it from the list of entries: */ @@ -2317,10 +2327,6 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_ irq_chip_pm_put(&desc->irq_data); module_put(desc->owner); return action; - -bad: - raw_spin_unlock_irqrestore(&desc->lock, flags); - return NULL; } /** -- 1.8.3.1
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