Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y

commit 2ce9d2272b98743b911196c49e7af5841381c206 upstream.

Some code (all error handling) submits CDBs that are allocated
on the stack.  This breaks with CB/CBI code that tries to create
URB directly from SCSI command buffer - which happens to be in
vmalloced memory with vmalloced kernel stacks.

Let's make copy of the command in usb_stor_CB_transport.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index 366395c..197fcfa 100644 (file)
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -922,10 +922,15 @@ int usb_stor_CB_transport(struct scsi_cmnd *srb, struct us_data *us)
 
        /* COMMAND STAGE */
        /* let's send the command via the control pipe */
+       /*
+        * Command is sometime (f.e. after scsi_eh_prep_cmnd) on the stack.
+        * Stack may be vmallocated.  So no DMA for us.  Make a copy.
+        */
+       memcpy(us->iobuf, srb->cmnd, srb->cmd_len);
        result = usb_stor_ctrl_transfer(us, us->send_ctrl_pipe,
                                      US_CBI_ADSC, 
                                      USB_TYPE_CLASS | USB_RECIP_INTERFACE, 0, 
-                                     us->ifnum, srb->cmnd, srb->cmd_len);
+                                     us->ifnum, us->iobuf, srb->cmd_len);
 
        /* check the return code for the command */
        US_DEBUGP("Call to usb_stor_ctrl_transfer() returned %d\n", result);