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authorThomas Gleixner <tglx@linutronix.de>2011-02-07 09:05:05 +0100
committerThomas Gleixner <tglx@linutronix.de>2011-02-19 12:58:08 +0100
commit1082687e8d6292a61759eb83358e7db39fed1bf4 (patch)
tree2a6ba19073820f116050b1730f3e08f97187ddb2 /kernel/irq/spurious.c
parent2b879eaf095878430c38cbd95e5c0fc4ce65ad8e (diff)
genirq: Plug race in report_bad_irq()
We cannot walk the action chain unlocked. Even if IRQ_INPROGRESS is set an action can be removed and we follow a null pointer. It's safe to take the lock there, because the code which removes the action will call synchronize_irq() which waits unlocked for IRQ_INPROGRESS going away. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq/spurious.c')
-rw-r--r--kernel/irq/spurious.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index 3089d3b9d5f3..2fbfda2716e1 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -139,15 +139,13 @@ static void poll_spurious_irqs(unsigned long dummy)
*
* (The other 100-of-100,000 interrupts may have been a correctly
* functioning device sharing an IRQ with the failing one)
- *
- * Called under desc->lock
*/
-
static void
__report_bad_irq(unsigned int irq, struct irq_desc *desc,
irqreturn_t action_ret)
{
struct irqaction *action;
+ unsigned long flags;
if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
printk(KERN_ERR "irq event %d: bogus return value %x\n",
@@ -159,6 +157,13 @@ __report_bad_irq(unsigned int irq, struct irq_desc *desc,
dump_stack();
printk(KERN_ERR "handlers:\n");
+ /*
+ * We need to take desc->lock here. note_interrupt() is called
+ * w/o desc->lock held, but IRQ_PROGRESS set. We might race
+ * with something else removing an action. It's ok to take
+ * desc->lock here. See synchronize_irq().
+ */
+ raw_spin_lock_irqsave(&desc->lock, flags);
action = desc->action;
while (action) {
printk(KERN_ERR "[<%p>]", action->handler);
@@ -167,6 +172,7 @@ __report_bad_irq(unsigned int irq, struct irq_desc *desc,
printk("\n");
action = action->next;
}
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
}
static void