patch "Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y" added to usb-linus

patch "Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 2ce9d2272b98743b911196c49e7af5841381c206 Mon Sep 17 00:00:00 2001
From: Petr Vandrovec <petr@vandrovec.name>
Date: Thu, 10 Nov 2016 13:57:14 -0800
Subject: Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y

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>
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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 ffd086733421..1a59f335b063 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -954,10 +954,15 @@ 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",
-- 
2.10.2