When panel probe happens after DSI probe, the DSI probe is deferred as per current design. In the probe defer path dsi device is destroyed. This NULL dsi device could be deferenced by the panel probe in the mipi_dsi_attach path.
Check for NULL dsi device before accessing it.
Reported-by: Jeffrey Hugo jhugo@codeaurora.org Tested-by: Jeffrey Hugo jhugo@codeaurora.org Signed-off-by: Abhinav Kumar abhinavk@codeaurora.org --- drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c index 80aa634..cc2569d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c @@ -769,7 +769,7 @@ bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len) void msm_dsi_manager_attach_dsi_device(int id, u32 device_flags) { struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id); - struct drm_device *dev = msm_dsi->dev; + struct drm_device *dev = msm_dsi ? msm_dsi->dev : NULL; struct msm_drm_private *priv; struct msm_kms *kms; struct drm_encoder *encoder;
On Wed, Mar 06, 2019 at 05:28:54PM -0800, Abhinav Kumar wrote:
When panel probe happens after DSI probe, the DSI probe is deferred as per current design. In the probe defer path dsi device is destroyed. This NULL dsi device could be deferenced by the panel probe in the mipi_dsi_attach path.
Check for NULL dsi device before accessing it.
It would be really nice to sort all of this out in a manner that's not sprinkling NULL checks around the driver. I spent 5 minutes looking around and couldn't really make sense of how all of these pieces interact, but this seems like it might be an architectural problem (perhaps since dpu was using its own panel stuff instead of drm_panel?).
Anyways, it'd be nice to fix that.
In the meantime, could you please add a big comment like the !dev check in this function explaining how this situation can come to pass? That way the knowledge isn't lost and whoever comes along to clean up all of these probe checks will have some clue as to what's going on.
Sean
Reported-by: Jeffrey Hugo jhugo@codeaurora.org Tested-by: Jeffrey Hugo jhugo@codeaurora.org Signed-off-by: Abhinav Kumar abhinavk@codeaurora.org
drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c index 80aa634..cc2569d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c @@ -769,7 +769,7 @@ bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len) void msm_dsi_manager_attach_dsi_device(int id, u32 device_flags) { struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
- struct drm_device *dev = msm_dsi->dev;
- struct drm_device *dev = msm_dsi ? msm_dsi->dev : NULL; struct msm_drm_private *priv; struct msm_kms *kms; struct drm_encoder *encoder;
-- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
On 2019-03-07 13:59, Sean Paul wrote:
On Wed, Mar 06, 2019 at 05:28:54PM -0800, Abhinav Kumar wrote:
When panel probe happens after DSI probe, the DSI probe is deferred as per current design. In the probe defer path dsi device is destroyed. This NULL dsi device could be deferenced by the panel probe in the mipi_dsi_attach path.
Check for NULL dsi device before accessing it.
It would be really nice to sort all of this out in a manner that's not sprinkling NULL checks around the driver. I spent 5 minutes looking around and couldn't really make sense of how all of these pieces interact, but this seems like it might be an architectural problem (perhaps since dpu was using its own panel stuff instead of drm_panel?).
Anyways, it'd be nice to fix that.
In the meantime, could you please add a big comment like the !dev check in this function explaining how this situation can come to pass? That way the knowledge isn't lost and whoever comes along to clean up all of these probe checks will have some clue as to what's going on.
Sean
[Abhinav] Sure Sean, will add a detailed comment to explain the scenario
Reported-by: Jeffrey Hugo jhugo@codeaurora.org Tested-by: Jeffrey Hugo jhugo@codeaurora.org Signed-off-by: Abhinav Kumar abhinavk@codeaurora.org
drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c index 80aa634..cc2569d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c @@ -769,7 +769,7 @@ bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len) void msm_dsi_manager_attach_dsi_device(int id, u32 device_flags) { struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
- struct drm_device *dev = msm_dsi->dev;
- struct drm_device *dev = msm_dsi ? msm_dsi->dev : NULL; struct msm_drm_private *priv; struct msm_kms *kms; struct drm_encoder *encoder;
-- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
On 3/7/2019 3:02 PM, Abhinav Kumar wrote:
On 2019-03-07 13:59, Sean Paul wrote:
On Wed, Mar 06, 2019 at 05:28:54PM -0800, Abhinav Kumar wrote:
When panel probe happens after DSI probe, the DSI probe is deferred as per current design. In the probe defer path dsi device is destroyed. This NULL dsi device could be deferenced by the panel probe in the mipi_dsi_attach path.
Check for NULL dsi device before accessing it.
It would be really nice to sort all of this out in a manner that's not sprinkling NULL checks around the driver. I spent 5 minutes looking around and couldn't really make sense of how all of these pieces interact, but this seems like it might be an architectural problem (perhaps since dpu was using its own panel stuff instead of drm_panel?).
Anyways, it'd be nice to fix that.
In the meantime, could you please add a big comment like the !dev check in this function explaining how this situation can come to pass? That way the knowledge isn't lost and whoever comes along to clean up all of these probe checks will have some clue as to what's going on.
Sean
[Abhinav] Sure Sean, will add a detailed comment to explain the scenario
Abhinav, it looks like this may have dropped off your radar. Do you know when you'll come back to it?
Reported-by: Jeffrey Hugo jhugo@codeaurora.org Tested-by: Jeffrey Hugo jhugo@codeaurora.org Signed-off-by: Abhinav Kumar abhinavk@codeaurora.org
drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c index 80aa634..cc2569d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c @@ -769,7 +769,7 @@ bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len) void msm_dsi_manager_attach_dsi_device(int id, u32 device_flags) { struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id); - struct drm_device *dev = msm_dsi->dev; + struct drm_device *dev = msm_dsi ? msm_dsi->dev : NULL; struct msm_drm_private *priv; struct msm_kms *kms; struct drm_encoder *encoder; -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
On 2019-05-29 13:43, Jeffrey Hugo wrote:
On 3/7/2019 3:02 PM, Abhinav Kumar wrote:
On 2019-03-07 13:59, Sean Paul wrote:
On Wed, Mar 06, 2019 at 05:28:54PM -0800, Abhinav Kumar wrote:
When panel probe happens after DSI probe, the DSI probe is deferred as per current design. In the probe defer path dsi device is destroyed. This NULL dsi device could be deferenced by the panel probe in the mipi_dsi_attach path.
Check for NULL dsi device before accessing it.
It would be really nice to sort all of this out in a manner that's not sprinkling NULL checks around the driver. I spent 5 minutes looking around and couldn't really make sense of how all of these pieces interact, but this seems like it might be an architectural problem (perhaps since dpu was using its own panel stuff instead of drm_panel?).
Anyways, it'd be nice to fix that.
In the meantime, could you please add a big comment like the !dev check in this function explaining how this situation can come to pass? That way the knowledge isn't lost and whoever comes along to clean up all of these probe checks will have some clue as to what's going on.
Sean
[Abhinav] Sure Sean, will add a detailed comment to explain the scenario
Abhinav, it looks like this may have dropped off your radar. Do you know when you'll come back to it?
Hi Jeff, Yes i will upload a v2 with a detailed comment as sean requested within this week.
Reported-by: Jeffrey Hugo jhugo@codeaurora.org Tested-by: Jeffrey Hugo jhugo@codeaurora.org Signed-off-by: Abhinav Kumar abhinavk@codeaurora.org
drivers/gpu/drm/msm/dsi/dsi_manager.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c index 80aa634..cc2569d 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_manager.c +++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c @@ -769,7 +769,7 @@ bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len) void msm_dsi_manager_attach_dsi_device(int id, u32 device_flags) { struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id); - struct drm_device *dev = msm_dsi->dev; + struct drm_device *dev = msm_dsi ? msm_dsi->dev : NULL; struct msm_drm_private *priv; struct msm_kms *kms; struct drm_encoder *encoder; -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
dri-devel@lists.freedesktop.org
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