4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: "Gustavo A. R. Silva" <garsi...@embeddedor.com>


[ Upstream commit 62a277d43d47e74972de44d33bd3763e31992414 ]

_xt_ is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after _xt_ has been null
checked.

This issue was detected with the help of Coccinelle.

Fixes: 4483320e241c ("dmaengine: Use Pointer xt after NULL check.")
Signed-off-by: Gustavo A. R. Silva <garsi...@embeddedor.com>
Acked-by: Ludovic Desroches <ludovic.desroc...@microchip.com>
Signed-off-by: Vinod Koul <vinod.k...@intel.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/dma/at_hdmac.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -709,7 +709,7 @@ atc_prep_dma_interleaved(struct dma_chan
                         unsigned long flags)
 {
        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
-       struct data_chunk       *first = xt->sgl;
+       struct data_chunk       *first;
        struct at_desc          *desc = NULL;
        size_t                  xfer_count;
        unsigned int            dwidth;
@@ -721,6 +721,8 @@ atc_prep_dma_interleaved(struct dma_chan
        if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
                return NULL;
 
+       first = xt->sgl;
+
        dev_info(chan2dev(chan),
                 "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, 
flags=0x%lx\n",
                __func__, &xt->src_start, &xt->dst_start, xt->numf,


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