diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2011-02-07 09:05:05 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-02-19 12:58:08 +0100 |
| commit | 1082687e8d6292a61759eb83358e7db39fed1bf4 (patch) | |
| tree | 2a6ba19073820f116050b1730f3e08f97187ddb2 /kernel/irq/spurious.c | |
| parent | 2b879eaf095878430c38cbd95e5c0fc4ce65ad8e (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.c | 12 |
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 |