Error routes through omap3isp ccdc.

2011-07-11 Thread Jonathan Cameron 
Hi All,

Came across this when my camera driver failed to load..

Following causes a kernel panic.

Set up link between cdcc and ccdc output to memory.
(at this point intitializing a capture gives an invalid
arguement error which is fine.)

Now set the format on ISP CCDC/0 to SGRBG10 752x480 (doubt what these
settings are actually matters).  Actually come to think of it, this
may only be relevant as otherwise, the format of my attempted stream
setup from userspace doesn't matter.

Blithely attempt to grab frames from userspace off the ccdc output.
(note it has no input.)

Null pointer exception occurs because:

pad = media_entity_remote_source(ccdc-pads[CCDC_PAD_SINK]);
in 
static void ccdc_configure(struct isp_ccdc_device *ccdc)

returns null and this is not checked.

Obvious local fix is to check the value of pad and allow ccdc_configure
to return an error + pass this up out of ccdc_set_stream.

Something like the following does the trick.
(not sure error code is right choice!)

Patch is against todays linux-next + a few unconnected things to make
that tree actually build for the beagle xm.

Grep isn't indicating any exactly matching cases to this problem, so
the rest of the tree may be fine.

 [PATCH] omap3isp: check if there is actually a source for ispccdc when
 setting up the link.

Without this if no source actually exists and the ccdc is configured
to output to memory, a read from userspace will cause a null pointer
exception.

Signed-off-by: Jonathan Cameron ji...@cam.ac.uk
---
 drivers/media/video/omap3isp/ispccdc.c |9 +++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/media/video/omap3isp/ispccdc.c 
b/drivers/media/video/omap3isp/ispccdc.c
index 6766247..2703a94 100644
--- a/drivers/media/video/omap3isp/ispccdc.c
+++ b/drivers/media/video/omap3isp/ispccdc.c
@@ -1110,7 +1110,7 @@ static const u32 ccdc_sgbrg_pattern =
ISPCCDC_COLPTN_R_Ye   ISPCCDC_COLPTN_CP3PLC2_SHIFT |
ISPCCDC_COLPTN_Gr_Cy  ISPCCDC_COLPTN_CP3PLC3_SHIFT;
 
-static void ccdc_configure(struct isp_ccdc_device *ccdc)
+static int ccdc_configure(struct isp_ccdc_device *ccdc)
 {
struct isp_device *isp = to_isp_device(ccdc);
struct isp_parallel_platform_data *pdata = NULL;
@@ -1127,6 +1127,8 @@ static void ccdc_configure(struct isp_ccdc_device *ccdc)
u32 ccdc_pattern;
 
pad = media_entity_remote_source(ccdc-pads[CCDC_PAD_SINK]);
+   if (pad == NULL)
+   return -ENODEV;
sensor = media_entity_to_v4l2_subdev(pad-entity);
if (ccdc-input == CCDC_INPUT_PARALLEL)
pdata = ((struct isp_v4l2_subdevs_group *)sensor-host_priv)
@@ -1257,6 +1259,7 @@ unlock:
spin_unlock_irqrestore(ccdc-lsc.req_lock, flags);
 
ccdc_apply_controls(ccdc);
+   return 0;
 }
 
 static void __ccdc_enable(struct isp_ccdc_device *ccdc, int enable)
@@ -1726,7 +1729,9 @@ static int ccdc_set_stream(struct v4l2_subdev *sd, int 
enable)
isp_reg_set(isp, OMAP3_ISP_IOMEM_CCDC, ISPCCDC_CFG,
ISPCCDC_CFG_VDLC);
 
-   ccdc_configure(ccdc);
+   ret = ccdc_configure(ccdc);
+   if (ret  0)
+   return ret;
 
/* TODO: Don't configure the video port if all of its output
 * links are inactive.
-- 
1.7.3.4

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Re: Error routes through omap3isp ccdc.

2011-07-11 Thread Laurent Pinchart 
Hi Jonathan,

On Monday 11 July 2011 12:41:49 Jonathan Cameron wrote:
 Hi All,
 
 Came across this when my camera driver failed to load..
 
 Following causes a kernel panic.
 
 Set up link between cdcc and ccdc output to memory.
 (at this point intitializing a capture gives an invalid
 arguement error which is fine.)
 
 Now set the format on ISP CCDC/0 to SGRBG10 752x480 (doubt what these
 settings are actually matters).  Actually come to think of it, this
 may only be relevant as otherwise, the format of my attempted stream
 setup from userspace doesn't matter.
 
 Blithely attempt to grab frames from userspace off the ccdc output.
 (note it has no input.)
 
 Null pointer exception occurs because:
 
 pad = media_entity_remote_source(ccdc-pads[CCDC_PAD_SINK]);
 in
 static void ccdc_configure(struct isp_ccdc_device *ccdc)
 
 returns null and this is not checked.

Good catch, thanks.

 Obvious local fix is to check the value of pad and allow ccdc_configure
 to return an error + pass this up out of ccdc_set_stream.
 
 Something like the following does the trick.
 (not sure error code is right choice!)
 
 Patch is against todays linux-next + a few unconnected things to make
 that tree actually build for the beagle xm.
 
 Grep isn't indicating any exactly matching cases to this problem, so
 the rest of the tree may be fine.
 
  [PATCH] omap3isp: check if there is actually a source for ispccdc when
  setting up the link.
 
 Without this if no source actually exists and the ccdc is configured
 to output to memory, a read from userspace will cause a null pointer
 exception.

Thanks for the patch.

I think we should try to fix it in ispvideo.c instead. You could add a check 
to isp_video_validate_pipeline() to make sure that the pipeline has a video 
source.

 Signed-off-by: Jonathan Cameron ji...@cam.ac.uk
 ---
  drivers/media/video/omap3isp/ispccdc.c |9 +++--
  1 files changed, 7 insertions(+), 2 deletions(-)
 
 diff --git a/drivers/media/video/omap3isp/ispccdc.c
 b/drivers/media/video/omap3isp/ispccdc.c index 6766247..2703a94 100644
 --- a/drivers/media/video/omap3isp/ispccdc.c
 +++ b/drivers/media/video/omap3isp/ispccdc.c
 @@ -1110,7 +1110,7 @@ static const u32 ccdc_sgbrg_pattern =
   ISPCCDC_COLPTN_R_Ye   ISPCCDC_COLPTN_CP3PLC2_SHIFT |
   ISPCCDC_COLPTN_Gr_Cy  ISPCCDC_COLPTN_CP3PLC3_SHIFT;
 
 -static void ccdc_configure(struct isp_ccdc_device *ccdc)
 +static int ccdc_configure(struct isp_ccdc_device *ccdc)
  {
   struct isp_device *isp = to_isp_device(ccdc);
   struct isp_parallel_platform_data *pdata = NULL;
 @@ -1127,6 +1127,8 @@ static void ccdc_configure(struct isp_ccdc_device
 *ccdc) u32 ccdc_pattern;
 
   pad = media_entity_remote_source(ccdc-pads[CCDC_PAD_SINK]);
 + if (pad == NULL)
 + return -ENODEV;
   sensor = media_entity_to_v4l2_subdev(pad-entity);
   if (ccdc-input == CCDC_INPUT_PARALLEL)
   pdata = ((struct isp_v4l2_subdevs_group *)sensor-host_priv)
 @@ -1257,6 +1259,7 @@ unlock:
   spin_unlock_irqrestore(ccdc-lsc.req_lock, flags);
 
   ccdc_apply_controls(ccdc);
 + return 0;
  }
 
  static void __ccdc_enable(struct isp_ccdc_device *ccdc, int enable)
 @@ -1726,7 +1729,9 @@ static int ccdc_set_stream(struct v4l2_subdev *sd,
 int enable) isp_reg_set(isp, OMAP3_ISP_IOMEM_CCDC, ISPCCDC_CFG,
   ISPCCDC_CFG_VDLC);
 
 - ccdc_configure(ccdc);
 + ret = ccdc_configure(ccdc);
 + if (ret  0)
 + return ret;
 
   /* TODO: Don't configure the video port if all of its output
* links are inactive.

-- 
Regards,

Laurent Pinchart
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Re: Error routes through omap3isp ccdc.

2011-07-11 Thread Laurent Pinchart 
On Monday 11 July 2011 12:54:42 Laurent Pinchart wrote:
 On Monday 11 July 2011 12:41:49 Jonathan Cameron wrote:

[snip]

 I think we should try to fix it in ispvideo.c instead. You could add a
 check to isp_video_validate_pipeline() to make sure that the pipeline has
 a video source.

And I forgot to mention, I can send a patch if you don't want to write it.

-- 
Regards,

Laurent Pinchart
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Re: Error routes through omap3isp ccdc.

2011-07-11 Thread Jonathan Cameron 
On 07/11/11 11:57, Laurent Pinchart wrote:
 On Monday 11 July 2011 12:54:42 Laurent Pinchart wrote:
 On Monday 11 July 2011 12:41:49 Jonathan Cameron wrote:
 
 [snip]
 
 I think we should try to fix it in ispvideo.c instead. You could add a
 check to isp_video_validate_pipeline() to make sure that the pipeline has
 a video source.
 
 And I forgot to mention, I can send a patch if you don't want to write it.
 
Given I can't quite see why the validate_pipeline code would ever want to break
on source pad being null (which I think is what it is currently doing),
I'll leave it to you.  Really don't know this code well enough!

Thanks.

Jonathan
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