lkml.org 
[lkml]   [2019]   [Aug]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v5 1/3] genirq: enhance error recovery code in free irq
Date
__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
\
 
 \ /
  Last update: 2019-08-30 10:43    [W:0.083 / U:19.500 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site