* [PATCH] dpu1: dpu_encoder: fix a missing check on list iterator
@ 2022-03-27 7:32 Xiaomeng Tong
2022-04-11 0:56 ` Dmitry Baryshkov
0 siblings, 1 reply; 3+ messages in thread
From: Xiaomeng Tong @ 2022-03-27 7:32 UTC (permalink / raw)
To: robdclark, sean, airlied, daniel
Cc: quic_abhinavk, dmitry.baryshkov, swboyd, bjorn.andersson,
quic_khsieh, quic_kalyant, markyacoub, jsanka, linux-arm-msm,
dri-devel, freedreno, linux-kernel, Xiaomeng Tong, stable
The bug is here:
cstate = to_dpu_crtc_state(drm_crtc->state);
For the drm_for_each_crtc(), just like list_for_each_entry(),
the list iterator 'drm_crtc' will point to a bogus position
containing HEAD if the list is empty or no element is found.
This case must be checked before any use of the iterator,
otherwise it will lead to a invalid memory access.
To fix this bug, use a new variable 'iter' as the list iterator,
while use the origin variable 'drm_crtc' as a dedicated pointer
to point to the found element.
Cc: stable@vger.kernel.org
Fixes: b107603b4ad0f ("drm/msm/dpu: map mixer/ctl hw blocks in encoder modeset")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 1e648db439f9..d3fdb18e96f9 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -965,7 +965,7 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
struct dpu_kms *dpu_kms;
struct list_head *connector_list;
struct drm_connector *conn = NULL, *conn_iter;
- struct drm_crtc *drm_crtc;
+ struct drm_crtc *drm_crtc = NULL, *iter;
struct dpu_crtc_state *cstate;
struct dpu_global_state *global_state;
struct dpu_hw_blk *hw_pp[MAX_CHANNELS_PER_ENC];
@@ -1007,9 +1007,14 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
return;
}
- drm_for_each_crtc(drm_crtc, drm_enc->dev)
- if (drm_crtc->state->encoder_mask & drm_encoder_mask(drm_enc))
+ drm_for_each_crtc(iter, drm_enc->dev)
+ if (iter->state->encoder_mask & drm_encoder_mask(drm_enc)) {
+ drm_crtc = iter;
break;
+ }
+
+ if (!drm_crtc)
+ return;
/* Query resource that have been reserved in atomic check step. */
num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] dpu1: dpu_encoder: fix a missing check on list iterator
2022-03-27 7:32 [PATCH] dpu1: dpu_encoder: fix a missing check on list iterator Xiaomeng Tong
@ 2022-04-11 0:56 ` Dmitry Baryshkov
2022-04-11 1:20 ` Dmitry Baryshkov
0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Baryshkov @ 2022-04-11 0:56 UTC (permalink / raw)
To: Xiaomeng Tong, robdclark, sean, airlied, daniel
Cc: quic_abhinavk, swboyd, bjorn.andersson, quic_khsieh,
quic_kalyant, markyacoub, jsanka, linux-arm-msm, dri-devel,
freedreno, linux-kernel, stable
On 27/03/2022 10:32, Xiaomeng Tong wrote:
> The bug is here:
> cstate = to_dpu_crtc_state(drm_crtc->state);
>
> For the drm_for_each_crtc(), just like list_for_each_entry(),
> the list iterator 'drm_crtc' will point to a bogus position
> containing HEAD if the list is empty or no element is found.
> This case must be checked before any use of the iterator,
> otherwise it will lead to a invalid memory access.
>
> To fix this bug, use a new variable 'iter' as the list iterator,
> while use the origin variable 'drm_crtc' as a dedicated pointer
> to point to the found element.
>
> Cc: stable@vger.kernel.org
> Fixes: b107603b4ad0f ("drm/msm/dpu: map mixer/ctl hw blocks in encoder modeset")
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 1e648db439f9..d3fdb18e96f9 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -965,7 +965,7 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
> struct dpu_kms *dpu_kms;
> struct list_head *connector_list;
> struct drm_connector *conn = NULL, *conn_iter;
> - struct drm_crtc *drm_crtc;
> + struct drm_crtc *drm_crtc = NULL, *iter;
> struct dpu_crtc_state *cstate;
> struct dpu_global_state *global_state;
> struct dpu_hw_blk *hw_pp[MAX_CHANNELS_PER_ENC];
> @@ -1007,9 +1007,14 @@ static void dpu_encoder_virt_mode_set(struct drm_encoder *drm_enc,
> return;
> }
>
> - drm_for_each_crtc(drm_crtc, drm_enc->dev)
> - if (drm_crtc->state->encoder_mask & drm_encoder_mask(drm_enc))
> + drm_for_each_crtc(iter, drm_enc->dev)
> + if (iter->state->encoder_mask & drm_encoder_mask(drm_enc)) {
> + drm_crtc = iter;
> break;
> + }
> +
> + if (!drm_crtc)
> + return;
>
> /* Query resource that have been reserved in atomic check step. */
> num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] dpu1: dpu_encoder: fix a missing check on list iterator
2022-04-11 0:56 ` Dmitry Baryshkov
@ 2022-04-11 1:20 ` Dmitry Baryshkov
0 siblings, 0 replies; 3+ messages in thread
From: Dmitry Baryshkov @ 2022-04-11 1:20 UTC (permalink / raw)
To: Xiaomeng Tong, robdclark, sean, airlied, daniel
Cc: quic_abhinavk, swboyd, bjorn.andersson, quic_khsieh,
quic_kalyant, markyacoub, jsanka, linux-arm-msm, dri-devel,
freedreno, linux-kernel, stable
On 11/04/2022 03:56, Dmitry Baryshkov wrote:
> On 27/03/2022 10:32, Xiaomeng Tong wrote:
>> The bug is here:
>> cstate = to_dpu_crtc_state(drm_crtc->state);
>>
>> For the drm_for_each_crtc(), just like list_for_each_entry(),
>> the list iterator 'drm_crtc' will point to a bogus position
>> containing HEAD if the list is empty or no element is found.
>> This case must be checked before any use of the iterator,
>> otherwise it will lead to a invalid memory access.
>>
>> To fix this bug, use a new variable 'iter' as the list iterator,
>> while use the origin variable 'drm_crtc' as a dedicated pointer
>> to point to the found element.
>>
>> Cc: stable@vger.kernel.org
>> Fixes: b107603b4ad0f ("drm/msm/dpu: map mixer/ctl hw blocks in encoder
>> modeset")
>> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
On the other hand, this code has been removed in 5.18-rc1 in the commit
764332bf96244cbc8baf08aa35844b29106da312.
>
>> ---
>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 11 ++++++++---
>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> index 1e648db439f9..d3fdb18e96f9 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> @@ -965,7 +965,7 @@ static void dpu_encoder_virt_mode_set(struct
>> drm_encoder *drm_enc,
>> struct dpu_kms *dpu_kms;
>> struct list_head *connector_list;
>> struct drm_connector *conn = NULL, *conn_iter;
>> - struct drm_crtc *drm_crtc;
>> + struct drm_crtc *drm_crtc = NULL, *iter;
>> struct dpu_crtc_state *cstate;
>> struct dpu_global_state *global_state;
>> struct dpu_hw_blk *hw_pp[MAX_CHANNELS_PER_ENC];
>> @@ -1007,9 +1007,14 @@ static void dpu_encoder_virt_mode_set(struct
>> drm_encoder *drm_enc,
>> return;
>> }
>> - drm_for_each_crtc(drm_crtc, drm_enc->dev)
>> - if (drm_crtc->state->encoder_mask & drm_encoder_mask(drm_enc))
>> + drm_for_each_crtc(iter, drm_enc->dev)
>> + if (iter->state->encoder_mask & drm_encoder_mask(drm_enc)) {
>> + drm_crtc = iter;
>> break;
>> + }
>> +
>> + if (!drm_crtc)
>> + return;
>> /* Query resource that have been reserved in atomic check step. */
>> num_pp = dpu_rm_get_assigned_resources(&dpu_kms->rm, global_state,
>
>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-03-27 7:32 [PATCH] dpu1: dpu_encoder: fix a missing check on list iterator Xiaomeng Tong
2022-04-11 0:56 ` Dmitry Baryshkov
2022-04-11 1:20 ` Dmitry Baryshkov
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