Skip to contentSkip to conversation

linux: restrict IRQ probing

PATCH New Jan Beulich 1 participant 1 message Oct 2, 2008 Xen hypervisor interface

lore
Share & tools
lore

Jan Beulich

author
#0 lore raw

PATCH 1/1 linux: restrict IRQ probing

Since IRQ probing may touch all currently unused interrupts, we must prevent probing for those where it doesn't make sense (to avoid triggering BUG()s or de-referencing NULL function pointers):
- dynamic IRQs must never be probed
- physical IRQs should only be probed when registered or identity-mapped

I haven't got feedback from the reporting party, yet, but as the change seems correct in any case, I thought I'd submit it right away.

As usual, written and tested on 2.6.27-rc8 and made apply to the 2.6.18 tree without further testing.

Signed-off-by Jan Beulich <[email protected]>
drivers/xen/core/evtchn.c +12 -1
Index: head-2008-10-01/drivers/xen/core/evtchn.c
===================================================================
@@ -784,7 +784,16 @@ static struct irq_chip dynirq_chip = {
 
 void evtchn_register_pirq(int irq)
 {
+	struct irq_desc *desc;
+	unsigned long flags;
+
 	irq_info[irq] = mk_irq_info(IRQT_PIRQ, irq, 0);
+
+	/* Cannot call set_irq_probe(), as that's marked __init. */
+	desc = irq_desc + irq;
+	spin_lock_irqsave(&desc->lock, flags);
+	desc->status &= ~IRQ_NOPROBE;
+	spin_unlock_irqrestore(&desc->lock, flags);
 }
 
 #if defined(CONFIG_X86_IO_APIC)

@@ -1177,7 +1186,7 @@ void __init xen_init_IRQ(void)
 	for (i = DYNIRQ_BASE; i < (DYNIRQ_BASE + NR_DYNIRQS); i++) {
 		irq_bindcount[i] = 0;
 
-		irq_desc[i].status = IRQ_DISABLED;
+		irq_desc[i].status = IRQ_DISABLED|IRQ_NOPROBE;
 		irq_desc[i].action = NULL;
 		irq_desc[i].depth = 1;
 		irq_desc[i].chip = &dynirq_type;

@@ -1196,6 +1105,8 @@ void __init xen_init_IRQ(void)
 #endif
 
 		irq_desc[i].status = IRQ_DISABLED;
+		if (!identity_mapped_irq(i))
+			irq_desc[i].status |= IRQ_NOPROBE;
 		irq_desc[i].action = NULL;
 		irq_desc[i].depth = 1;
 		irq_desc[i].chip = &pirq_type;