[PATCH 3.16 246/366] usb: musb: host: fix potential NULL pointer dereference

Ben Hutchings
2018-10-14T23:12:05Z

From: Bin Liu <b-liu@ti.com>

commit 2b63f1329df2cd814c1f8353fae4853ace6521d1 upstream.

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: f283862f3b5c ("usb: musb: NAK timeout scheme on bulk TX endpoint")
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/musb/musb_host.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1002,7 +1002,9 @@ static void musb_bulk_nak_timeout(struct
/* 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);
}
}