xhci: fix off by one check when adding a secondary interrupter.

The sanity check of interrupter index when adding a new interrupter is
off by one. intr_num needs to be smaller than xhci->max_interrupter to
fit the array of interrupters.

Luckily this doesn't cause any real word harm as xhci_add_interrupter()
is always called with a intr_num value smaller than xhci->max_interrupters
in any current kernel.

Should not be needed for stable as 6.7 kernel and older only supports
one interrupter, with intr_num always being zero.

Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/linux-usb/[email protected]/
Fixes: 4bf398e ("xhci: split allocate interrupter into separate alloacte and add parts")
Signed-off-by: Mathias Nyman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: matnyman

drivers/usb/host/xhci-mem.c

@@ -2322,7 +2322,7 @@ xhci_add_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir,
 	u64 erst_base;
 	u32 erst_size;
 
-	if (intr_num > xhci->max_interrupters) {
+	if (intr_num >= xhci->max_interrupters) {
 		xhci_warn(xhci, "Can't add interrupter %d, max interrupters %d\n",
 			  intr_num, xhci->max_interrupters);
 		return -EINVAL;