This patch (as1517) fixes an error in the USB scatter-gather library. The library code uses urb->dev to determine whether or nor an URB is currently active; the completion handler sets urb->dev to NULL. However the core unlinking routines need to use urb->dev. Since unlinking always racing with completion, the completion handler must not clear urb->dev -- it can lead to invalid memory accesses when a transfer has to be cancelled. This patch fixes the problem by getting rid of the lines that clear urb->dev after urb has been submitted. As a result we may end up trying to unlink an URB that failed in submission or that has already completed, so an extra check is added after each unlink to avoid printing an error message when this happens. Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Reported-and-tested-by: Illia Zaitsev <I.Zaitsev@xxxxxxxxxxxxx> CC: <stable@xxxxxxxxxxxxxxx> --- drivers/usb/core/message.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) Index: usb-3.3/drivers/usb/core/message.c =================================================================== --- usb-3.3.orig/drivers/usb/core/message.c +++ usb-3.3/drivers/usb/core/message.c @@ -308,7 +308,8 @@ static void sg_complete(struct urb *urb) retval = usb_unlink_urb(io->urbs [i]); if (retval != -EINPROGRESS && retval != -ENODEV && - retval != -EBUSY) + retval != -EBUSY && + retval != -EIDRM) dev_err(&io->dev->dev, "%s, unlink --> %d\n", __func__, retval); @@ -317,7 +318,6 @@ static void sg_complete(struct urb *urb) } spin_lock(&io->lock); } - urb->dev = NULL; /* on the last completion, signal usb_sg_wait() */ io->bytes += urb->actual_length; @@ -524,7 +524,6 @@ void usb_sg_wait(struct usb_sg_request * case -ENXIO: /* hc didn't queue this one */ case -EAGAIN: case -ENOMEM: - io->urbs[i]->dev = NULL; retval = 0; yield(); break; @@ -542,7 +541,6 @@ void usb_sg_wait(struct usb_sg_request * /* fail any uncompleted urbs */ default: - io->urbs[i]->dev = NULL; io->urbs[i]->status = retval; dev_dbg(&io->dev->dev, "%s, submit --> %d\n", __func__, retval); -- 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
