From: Toby Gray commit 577045c0a76e34294f902a7d5d60e90b04d094d0 upstream. Certain USB devices, such as the Nokia X6 mobile phone, don't expose any endpoint descriptors on some of their interfaces. If the ACM driver is forced to probe all interfaces on a device the a NULL pointer dereference will occur when the ACM driver attempts to use the endpoint of the alternative settings. One way to get the ACM driver to probe all the interfaces is by using the /sys/bus/usb/drivers/cdc_acm/new_id interface. This patch checks that the endpoint pointer for the current alternate settings is non-NULL before using it. Signed-off-by: Toby Gray Cc: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -971,7 +971,8 @@ static int acm_probe(struct usb_interfac } if (!buflen) { - if (intf->cur_altsetting->endpoint->extralen && + if (intf->cur_altsetting->endpoint && + intf->cur_altsetting->endpoint->extralen && intf->cur_altsetting->endpoint->extra) { dev_dbg(&intf->dev, "Seeking extra descriptors on endpoint\n"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/