[PATCH] [media] saa7146: fix a possible NULL pointer reference in saa7146_set_position

[Ethan Zhao <ethan.kernel@gmail.com>]

Function saa7146_format_by_fourcc() may return NULL, reference of the returned
result would cause NULL pointer issue without checking.

Signed-off-by: Ethan Zhao <ethan.kernel@gmail.com>
---
 drivers/media/common/saa7146/saa7146_hlp.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/media/common/saa7146/saa7146_hlp.c b/drivers/media/common/saa7146/saa7146_hlp.c
index be746d1..3e23eab 100644
--- a/drivers/media/common/saa7146/saa7146_hlp.c
+++ b/drivers/media/common/saa7146/saa7146_hlp.c
@@ -575,6 +575,7 @@ static void saa7146_set_position(struct saa7146_dev *dev, int w_x, int w_y, int
 	 */
 	u32 base = (u32)(unsigned long)vv->ov_fb.base;
 
+	int which = 1;
 	struct	saa7146_video_dma vdma1;
 
 	/* calculate memory offsets for picture, look if we shall top-down-flip */
@@ -608,10 +609,14 @@ static void saa7146_set_position(struct saa7146_dev *dev, int w_x, int w_y, int
 		vdma1.pitch *= -1;
 	}
 
-	vdma1.base_page = sfmt->swap;
+	if (sfmt)
+		vdma1.base_page = sfmt->swap;
+	else
+		which = 0;
+
 	vdma1.num_line_byte = (vv->standard->v_field<<16)+vv->standard->h_pixels;
 
-	saa7146_write_out_dma(dev, 1, &vdma1);
+	saa7146_write_out_dma(dev, which, &vdma1);
 }
 
 static void saa7146_set_output_format(struct saa7146_dev *dev, unsigned long palette)
-- 
1.8.3.4 (Apple Git-47)