usb: catch attempts to submit urbs with a vmalloc'd transfer buffer

Save someone else the debug cycles of figuring out why a driver's transfer request is failing or causing undefined system behavior. Buffers submitted for dma must come from GFP allocated / DMA-able memory. Return -EAGAIN matching the return value for dma_mapping_error() cases. Acked-by: Alan Stern <[email protected]> Cc: Sarah Sharp <[email protected]> Cc: Mathias Nyman <[email protected]> Signed-off-by: Dan Williams <[email protected]> Signed-off-by: Mathias Nyman <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
neviim · May 20, 2014 · 29d2fef · 29d2fef
1 parent 654a55d
commit 29d2fef
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
@@ -1502,6 +1502,9 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
 					ret = -EAGAIN;
 				else
 					urb->transfer_flags |= URB_DMA_MAP_PAGE;
+			} else if (is_vmalloc_addr(urb->transfer_buffer)) {
+				WARN_ONCE(1, "transfer buffer not dma capable\n");
+				ret = -EAGAIN;
 			} else {
 				urb->transfer_dma = dma_map_single(
 						hcd->self.controller,