musb_start_urb() doesn't check the pass-in parameter if it is NULL. But in musb_bulk_nak_timeout() the parameter passed to musb_start_urb() is returned from first_qh(), which could be NULL. So wrap the musb_start_urb() call here with a if condition check to avoid the potential NULL pointer dereference. Fixes: f283862f3b5cb("usb: musb: NAK timeout scheme on bulk TX endpoint") Cc: stable@xxxxxxxxxxxxxxx # v3.7+ Signed-off-by: Bin Liu <b-liu@xxxxxx> --- drivers/usb/musb/musb_host.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 4fa372c845e1..e7f99d55922a 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -990,7 +990,9 @@ static void musb_bulk_nak_timeout(struct musb *musb, struct musb_hw_ep *ep, /* set tx_reinit and schedule the next qh */ ep->tx_reinit = 1; } - musb_start_urb(musb, is_in, next_qh); + + if (next_qh) + musb_start_urb(musb, is_in, next_qh); } } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html