If hcd_endpoint_disable() is called at the same time that an URB is
submitted for that endpoint, there is a nasty race.
hcd_endpoint_disable() sets the endpoint maxpacket size to 0, in order to
prevent further submissions. But meanwhile, the HC driver is trying to
packetize the original request into maxpacket-sized packets. If maxpacket
is 0, the driver will hang.
This patch fixes the problem for UHCI. Something equivalent is needed for
the other HC drivers.
Alan Stern
===== uhci-hcd.c 1.59 vs edited =====
--- 1.59/drivers/usb/host/uhci-hcd.c Wed Aug 6 14:49:27 2003
+++ edited/drivers/usb/host/uhci-hcd.c Fri Aug 8 10:29:57 2003
@@ -806,6 +806,9 @@
int len = urb->transfer_buffer_length;
dma_addr_t data = urb->transfer_dma;
+ if (maxsze <= 0)
+ return -EMSGSIZE;
+
/* The "pipe" thing contains the destination in bits 8--18 */
destination = (urb->pipe & PIPE_DEVEP_MASK) | USB_PID_SETUP;
@@ -1080,6 +1083,8 @@
if (len < 0)
return -EINVAL;
+ if (maxsze <= 0)
+ return -EMSGSIZE;
/* The "pipe" thing contains the destination in bits 8--18 */
destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);
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