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 <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/linux-usb/e9771296-586d-456a-ac24-a82de79bb2e6@moroto.mountain/
Fixes: 4bf398e15aa4 ("xhci: split allocate interrupter into separate alloacte and add parts")
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240125152737.2983959-3-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index d00d4d93723669b73199c8c723049028f7d8e792..a7716202a8dd58d74f3d31fd48d0833de89db2be 100644 (file)
--- a/drivers/usb/host/xhci-mem.c
+++ b/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;