pnpacpi: fix potential corruption on "pnpacpi: exceeded the max number of IRQ resources 2"

PNP_MAX_IRQ is 2
If a device invokes pnpacpi_parse_allocated_irqresource() 0, 1, or 2 times, we are happy.
The 3rd time, we will fail and print "pnpacpi: exceeded the max number of IRQ resources: 2"
The 4th and subsequent calls (if this ever happened) would silently scribble on
irq_resource[2], which doesn't actualy exist.

Found-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/pnp/pnpacpi/rsparser.c b/drivers/pnp/pnpacpi/rsparser.c
index 2dcd1960aca8..98cbc9f18eed 100644
--- a/drivers/pnp/pnpacpi/rsparser.c
+++ b/drivers/pnp/pnpacpi/rsparser.c
@@ -84,10 +84,12 @@ static void pnpacpi_parse_allocated_irqresource(struct pnp_resource_table *res,
         while (!(res->irq_resource[i].flags & IORESOURCE_UNSET) &&
                i < PNP_MAX_IRQ)
                 i++;
-        if (i >= PNP_MAX_IRQ && !warned) {
-                printk(KERN_WARNING "pnpacpi: exceeded the max number of IRQ "
-                                "resources: %d \n", PNP_MAX_IRQ);
-                warned = 1;
+        if (i >= PNP_MAX_IRQ) {
+                if (!warned) {
+                        printk(KERN_WARNING "pnpacpi: exceeded the max number"
+                                " of IRQ resources: %d\n", PNP_MAX_IRQ);
+                        warned = 1;
+                }
                 return;
         }
         /*