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Subject[ 031/149] USB: ums_realtek: do not use stack memory for DMA in __do_config_autodelink
3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Josh Boyer <jwboyer@redhat.com>

commit 4898e07174b79013afd2b422ef6c4336ef8e6783 upstream.

__do_config_autodelink passes the data variable to the transport function.
If the calling functions pass a stack variable, this will eventually trigger
a DMA-API debug backtrace for mapping stack memory in the DMA buffer. Fix
this by calling kmemdup for the passed data instead.

Signed-off-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/storage/realtek_cr.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/usb/storage/realtek_cr.c
+++ b/drivers/usb/storage/realtek_cr.c
@@ -509,9 +509,14 @@ static int __do_config_autodelink(struct
int retval;
u16 addr = 0xFE47;
u8 cmnd[12] = {0};
+ u8 *buf;

US_DEBUGP("%s, addr = 0x%x, len = %d\n", __FUNCTION__, addr, len);

+ buf = kmemdup(data, len, GFP_NOIO);
+ if (!buf)
+ return USB_STOR_TRANSPORT_ERROR;
+
cmnd[0] = 0xF0;
cmnd[1] = 0x0E;
cmnd[2] = (u8)(addr >> 8);
@@ -519,7 +524,8 @@ static int __do_config_autodelink(struct
cmnd[4] = (u8)(len >> 8);
cmnd[5] = (u8)len;

- retval = rts51x_bulk_transport_special(us, 0, cmnd, 12, data, len, DMA_TO_DEVICE, NULL);
+ retval = rts51x_bulk_transport_special(us, 0, cmnd, 12, buf, len, DMA_TO_DEVICE, NULL);
+ kfree(buf);
if (retval != USB_STOR_TRANSPORT_GOOD) {
return -EIO;
}



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