[PATCH 3.10 123/319] Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y

Willy Tarreau
2017-02-05T19:28:49Z

From: Petr Vandrovec <petr@vandrovec.name>

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: Willy Tarreau <w@1wt.eu>
---
drivers/usb/storage/transport.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index b1d815e..8988b26 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -919,10 +919,15 @@ 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 */
usb_stor_dbg(us, "Call to usb_stor_ctrl_transfer() returned %d\n",
--
2.8.0.rc2.1.gbe9624a