* [PATCH v2] drm/msm/dp: populate connector of struct dp_panel
@ 2021-12-29 19:17 Kuogee Hsieh
2022-01-05 21:34 ` Stephen Boyd
0 siblings, 1 reply; 3+ messages in thread
From: Kuogee Hsieh @ 2021-12-29 19:17 UTC (permalink / raw)
To: robdclark, sean, swboyd, vkoul, daniel, airlied, agross,
dmitry.baryshkov, bjorn.andersson
Cc: quic_sbillaka, linux-arm-msm, quic_abhinavk, dri-devel,
quic_khsieh, aravindh, freedreno, linux-kernel
There is kernel crashed due to unable to handle kernel NULL
pointer dereference of dp_panel->connector while running DP link
layer compliance test case 4.2.2.6 (EDID Corruption Detection).
This patch fixes this problem by populating connector of dp_panel.
[drm:dp_panel_read_sink_caps] *ERROR* panel edid read failed
Unable to handle kernel NULL pointer dereference at virtual address 00000000000006e1
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
user pgtable: 4k pages, 39-bit VAs, pgdp=0000000115f25000
[00000000000006e1] pgd=00000001174fe003, p4d=00000001174fe003, pud=00000001174fe003, pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
{...]
Changes in V2:
-- populate panel connector at msm_dp_modeset_init() instead of at dp_panel_read_sink_caps()
Fixes: 7948fe12d47 ("drm/msm/dp: return correct edid checksum after corrupted edid checksum read")
Signee-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
---
drivers/gpu/drm/msm/dp/dp_display.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 3449d3f..c282bbf 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1495,36 +1495,41 @@ void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
}
}
-int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
+int msm_dp_modeset_init(struct msm_dp *dp, struct drm_device *dev,
struct drm_encoder *encoder)
{
struct msm_drm_private *priv;
+ struct dp_display_private *dp_display;
int ret;
- if (WARN_ON(!encoder) || WARN_ON(!dp_display) || WARN_ON(!dev))
+ if (WARN_ON(!encoder) || WARN_ON(!dp) || WARN_ON(!dev))
return -EINVAL;
priv = dev->dev_private;
- dp_display->drm_dev = dev;
+ dp->drm_dev = dev;
+
+ dp_display = container_of(dp, struct dp_display_private, dp_display);
- ret = dp_display_request_irq(dp_display);
+ ret = dp_display_request_irq(dp);
if (ret) {
DRM_ERROR("request_irq failed, ret=%d\n", ret);
return ret;
}
- dp_display->encoder = encoder;
+ dp->encoder = encoder;
- dp_display->connector = dp_drm_connector_init(dp_display);
- if (IS_ERR(dp_display->connector)) {
- ret = PTR_ERR(dp_display->connector);
+ dp->connector = dp_drm_connector_init(dp);
+ if (IS_ERR(dp->connector)) {
+ ret = PTR_ERR(dp->connector);
DRM_DEV_ERROR(dev->dev,
"failed to create dp connector: %d\n", ret);
- dp_display->connector = NULL;
+ dp->connector = NULL;
return ret;
}
- priv->connectors[priv->num_connectors++] = dp_display->connector;
+ dp_display->panel->connector = dp->connector;
+
+ priv->connectors[priv->num_connectors++] = dp->connector;
return 0;
}
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] drm/msm/dp: populate connector of struct dp_panel
2021-12-29 19:17 [PATCH v2] drm/msm/dp: populate connector of struct dp_panel Kuogee Hsieh
@ 2022-01-05 21:34 ` Stephen Boyd
2022-01-06 17:13 ` Kuogee Hsieh
0 siblings, 1 reply; 3+ messages in thread
From: Stephen Boyd @ 2022-01-05 21:34 UTC (permalink / raw)
To: Kuogee Hsieh, agross, airlied, bjorn.andersson, daniel,
dmitry.baryshkov, robdclark, sean, vkoul
Cc: quic_sbillaka, linux-arm-msm, quic_abhinavk, dri-devel,
linux-kernel, aravindh, freedreno
Quoting Kuogee Hsieh (2021-12-29 11:17:02)
> There is kernel crashed due to unable to handle kernel NULL
> pointer dereference of dp_panel->connector while running DP link
> layer compliance test case 4.2.2.6 (EDID Corruption Detection).
Can you explain how we get into that situation? Like
"We never assign struct dp_panel::connector, instead the connector is
stored in struct msm_dp::connector. When we run compliance testing test
case 4.2.2.6 dp_panel_handle_sink_request() won't have a valid edid set
in struct dp_panel::edid so we'll try to use the connectors
real_edid_checksum and hit a NULL pointer deref error because the
connector pointer is never assigned."
> This patch fixes this problem by populating connector of dp_panel.
>
> [drm:dp_panel_read_sink_caps] *ERROR* panel edid read failed
> Unable to handle kernel NULL pointer dereference at virtual address 00000000000006e1
> Mem abort info:
> ESR = 0x96000006
> EC = 0x25: DABT (current EL), IL = 32 bits
> SET = 0, FnV = 0
> EA = 0, S1PTW = 0
> Data abort info:
> ISV = 0, ISS = 0x00000006
> CM = 0, WnR = 0
> user pgtable: 4k pages, 39-bit VAs, pgdp=0000000115f25000
> [00000000000006e1] pgd=00000001174fe003, p4d=00000001174fe003, pud=00000001174fe003, pmd=0000000000000000
> Internal error: Oops: 96000006 [#1] PREEMPT SMP
This sort of stuff isn't really useful because it takes quite a few
lines to say "We hit a NULL pointer deref" which was already stated. I'd
rather have a clear description of what goes wrong and how setting the
pointer in msm_dp_modeset_init() fixes it.
> {...]
>
> Changes in V2:
> -- populate panel connector at msm_dp_modeset_init() instead of at dp_panel_read_sink_caps()
>
> Fixes: 7948fe12d47 ("drm/msm/dp: return correct edid checksum after corrupted edid checksum read")
> Signee-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> ---
> drivers/gpu/drm/msm/dp/dp_display.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 3449d3f..c282bbf 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -1495,36 +1495,41 @@ void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
> }
> }
>
> -int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
> +int msm_dp_modeset_init(struct msm_dp *dp, struct drm_device *dev,
> struct drm_encoder *encoder)
> {
> struct msm_drm_private *priv;
> + struct dp_display_private *dp_display;
> int ret;
>
> - if (WARN_ON(!encoder) || WARN_ON(!dp_display) || WARN_ON(!dev))
> + if (WARN_ON(!encoder) || WARN_ON(!dp) || WARN_ON(!dev))
> return -EINVAL;
>
> priv = dev->dev_private;
> - dp_display->drm_dev = dev;
> + dp->drm_dev = dev;
> +
> + dp_display = container_of(dp, struct dp_display_private, dp_display);
>
> - ret = dp_display_request_irq(dp_display);
> + ret = dp_display_request_irq(dp);
> if (ret) {
> DRM_ERROR("request_irq failed, ret=%d\n", ret);
> return ret;
> }
>
> - dp_display->encoder = encoder;
> + dp->encoder = encoder;
>
> - dp_display->connector = dp_drm_connector_init(dp_display);
> - if (IS_ERR(dp_display->connector)) {
> - ret = PTR_ERR(dp_display->connector);
> + dp->connector = dp_drm_connector_init(dp);
> + if (IS_ERR(dp->connector)) {
> + ret = PTR_ERR(dp->connector);
> DRM_DEV_ERROR(dev->dev,
> "failed to create dp connector: %d\n", ret);
> - dp_display->connector = NULL;
> + dp->connector = NULL;
> return ret;
> }
>
> - priv->connectors[priv->num_connectors++] = dp_display->connector;
> + dp_display->panel->connector = dp->connector;
This is the one line that matters I think? Can we reach the connector
for the dp device without going through the panel in
dp_panel_handle_sink_request()? That would reduce the number of struct
elements if possible.
> +
> + priv->connectors[priv->num_connectors++] = dp->connector;
Can we not rename all the local variables in this patch and do it later
or never? Reading this patch takes a long time because we have to make
sure nothing has actually changed with the rename of 'dp_display' to
'dp'.
> return 0;
> }
>
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] drm/msm/dp: populate connector of struct dp_panel
2022-01-05 21:34 ` Stephen Boyd
@ 2022-01-06 17:13 ` Kuogee Hsieh
0 siblings, 0 replies; 3+ messages in thread
From: Kuogee Hsieh @ 2022-01-06 17:13 UTC (permalink / raw)
To: Stephen Boyd, agross, airlied, bjorn.andersson, daniel,
dmitry.baryshkov, robdclark, sean, vkoul
Cc: quic_sbillaka, linux-arm-msm, quic_abhinavk, dri-devel,
linux-kernel, aravindh, freedreno
On 1/5/2022 1:34 PM, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-12-29 11:17:02)
>> There is kernel crashed due to unable to handle kernel NULL
>> pointer dereference of dp_panel->connector while running DP link
>> layer compliance test case 4.2.2.6 (EDID Corruption Detection).
> Can you explain how we get into that situation? Like
>
> "We never assign struct dp_panel::connector, instead the connector is
> stored in struct msm_dp::connector. When we run compliance testing test
> case 4.2.2.6 dp_panel_handle_sink_request() won't have a valid edid set
> in struct dp_panel::edid so we'll try to use the connectors
> real_edid_checksum and hit a NULL pointer deref error because the
> connector pointer is never assigned."
>
>> This patch fixes this problem by populating connector of dp_panel.
>>
>> [drm:dp_panel_read_sink_caps] *ERROR* panel edid read failed
>> Unable to handle kernel NULL pointer dereference at virtual address 00000000000006e1
>> Mem abort info:
>> ESR = 0x96000006
>> EC = 0x25: DABT (current EL), IL = 32 bits
>> SET = 0, FnV = 0
>> EA = 0, S1PTW = 0
>> Data abort info:
>> ISV = 0, ISS = 0x00000006
>> CM = 0, WnR = 0
>> user pgtable: 4k pages, 39-bit VAs, pgdp=0000000115f25000
>> [00000000000006e1] pgd=00000001174fe003, p4d=00000001174fe003, pud=00000001174fe003, pmd=0000000000000000
>> Internal error: Oops: 96000006 [#1] PREEMPT SMP
> This sort of stuff isn't really useful because it takes quite a few
> lines to say "We hit a NULL pointer deref" which was already stated. I'd
> rather have a clear description of what goes wrong and how setting the
> pointer in msm_dp_modeset_init() fixes it.
>
>> {...]
>>
>> Changes in V2:
>> -- populate panel connector at msm_dp_modeset_init() instead of at dp_panel_read_sink_caps()
>>
>> Fixes: 7948fe12d47 ("drm/msm/dp: return correct edid checksum after corrupted edid checksum read")
>> Signee-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
>> ---
>> drivers/gpu/drm/msm/dp/dp_display.c | 25 +++++++++++++++----------
>> 1 file changed, 15 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>> index 3449d3f..c282bbf 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -1495,36 +1495,41 @@ void msm_dp_debugfs_init(struct msm_dp *dp_display, struct drm_minor *minor)
>> }
>> }
>>
>> -int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
>> +int msm_dp_modeset_init(struct msm_dp *dp, struct drm_device *dev,
>> struct drm_encoder *encoder)
>> {
>> struct msm_drm_private *priv;
>> + struct dp_display_private *dp_display;
>> int ret;
>>
>> - if (WARN_ON(!encoder) || WARN_ON(!dp_display) || WARN_ON(!dev))
>> + if (WARN_ON(!encoder) || WARN_ON(!dp) || WARN_ON(!dev))
>> return -EINVAL;
>>
>> priv = dev->dev_private;
>> - dp_display->drm_dev = dev;
>> + dp->drm_dev = dev;
>> +
>> + dp_display = container_of(dp, struct dp_display_private, dp_display);
>>
>> - ret = dp_display_request_irq(dp_display);
>> + ret = dp_display_request_irq(dp);
>> if (ret) {
>> DRM_ERROR("request_irq failed, ret=%d\n", ret);
>> return ret;
>> }
>>
>> - dp_display->encoder = encoder;
>> + dp->encoder = encoder;
>>
>> - dp_display->connector = dp_drm_connector_init(dp_display);
>> - if (IS_ERR(dp_display->connector)) {
>> - ret = PTR_ERR(dp_display->connector);
>> + dp->connector = dp_drm_connector_init(dp);
>> + if (IS_ERR(dp->connector)) {
>> + ret = PTR_ERR(dp->connector);
>> DRM_DEV_ERROR(dev->dev,
>> "failed to create dp connector: %d\n", ret);
>> - dp_display->connector = NULL;
>> + dp->connector = NULL;
>> return ret;
>> }
>>
>> - priv->connectors[priv->num_connectors++] = dp_display->connector;
>> + dp_display->panel->connector = dp->connector;
> This is the one line that matters I think? Can we reach the connector
> for the dp device without going through the panel in
> dp_panel_handle_sink_request()? That would reduce the number of struct
> elements if possible.
I tried, but very difficulty. It will take more text section space.
>
>> +
>> + priv->connectors[priv->num_connectors++] = dp->connector;
> Can we not rename all the local variables in this patch and do it later
> or never? Reading this patch takes a long time because we have to make
> sure nothing has actually changed with the rename of 'dp_display' to
> 'dp'.
>
>> return 0;
>> }
>>
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-12-29 19:17 [PATCH v2] drm/msm/dp: populate connector of struct dp_panel Kuogee Hsieh
2022-01-05 21:34 ` Stephen Boyd
2022-01-06 17:13 ` Kuogee Hsieh
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