[patch 13/18] PNPACPI: ignore _PRS interrupt numbers larger than PNP_IRQ_NR

Bjorn Helgaas
2008-06-04T22:11:59Z

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ACPI Extended Interrupt Descriptors can encode 32-bit interrupt
numbers, so an interrupt number may exceed the size of the bitmap
we use to track possible IRQ settings.

To avoid corrupting memory, complain and ignore too-large interrupt
numbers.

There's similar code in pnpacpi_parse_irq_option(), but I didn't
change that because the small IRQ descriptor can only encode
IRQs 0-15, which do not exceed bitmap size.

In the future, we could handle IRQ numbers greater than PNP_IRQ_NR
by replacing the bitmap with a table or list.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-by: Rene Herman <rene.herman@gmail.com>

Index: work10/drivers/pnp/pnpacpi/rsparser.c
===================================================================
--- work10.orig/drivers/pnp/pnpacpi/rsparser.c 2008-05-30 13:23:34.000000000 -0600
+++ work10/drivers/pnp/pnpacpi/rsparser.c 2008-05-30 14:45:52.000000000 -0600
@@ -421,9 +421,16 @@ static __init void pnpacpi_parse_ext_irq
return;

bitmap_zero(map.bits, PNP_IRQ_NR);
- for (i = 0; i < p->interrupt_count; i++)
- if (p->interrupts[i])
- __set_bit(p->interrupts[i], map.bits);
+ for (i = 0; i < p->interrupt_count; i++) {
+ if (p->interrupts[i]) {
+ if (p->interrupts[i] < PNP_IRQ_NR)
+ __set_bit(p->interrupts[i], map.bits);
+ else
+ dev_err(&dev->dev, "ignoring IRQ %d option "
+ "(too large for %d entry bitmap)\n",
+ p->interrupts[i], PNP_IRQ_NR);
+ }
+ }

flags = irq_flags(p->triggering, p->polarity, p->sharable);
pnp_register_irq_resource(dev, option, &map, flags);

--