* [PATCH] coresight: tpdm: fix invalid MMIO access issue
@ 2026-04-07 4:47 Jie Gan
2026-04-07 8:10 ` Leo Yan
0 siblings, 1 reply; 5+ messages in thread
From: Jie Gan @ 2026-04-07 4:47 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Leo Yan,
Alexander Shishkin, Tingwei Zhang
Cc: coresight, linux-arm-kernel, linux-kernel, Jie Gan
Create the csdev_access struct only when a valid MMIO resource is
available. In tpdm_probe(), base is uninitialized for static TPDM
instances that lack an MMIO resource, causing csdev_access to be
created with a garbage address and potentially leading to
unexpected issues.
Fixes: 14ae052f7947 ("coresight: tpdm: add static tpdm support")
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
drivers/hwtracing/coresight/coresight-tpdm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index 9b16f368a58b..eaf7210af648 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -1430,6 +1430,7 @@ static int tpdm_probe(struct device *dev, struct resource *res)
if (ret)
return ret;
+ desc.access = CSDEV_ACCESS_IOMEM(base);
if (tpdm_has_dsb_dataset(drvdata))
of_property_read_u32(drvdata->dev->of_node,
"qcom,dsb-msrs-num", &drvdata->dsb_msr_num);
@@ -1452,7 +1453,6 @@ static int tpdm_probe(struct device *dev, struct resource *res)
desc.ops = &tpdm_cs_ops;
desc.pdata = dev->platform_data;
desc.dev = dev;
- desc.access = CSDEV_ACCESS_IOMEM(base);
if (res)
desc.groups = tpdm_attr_grps;
else
---
base-commit: 816f193dd0d95246f208590924dd962b192def78
change-id: 20260407-fix-potential-issue-in-tpdm-b07b44416051
Best regards,
--
Jie Gan <jie.gan@oss.qualcomm.com>
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] coresight: tpdm: fix invalid MMIO access issue
2026-04-07 4:47 [PATCH] coresight: tpdm: fix invalid MMIO access issue Jie Gan
@ 2026-04-07 8:10 ` Leo Yan
2026-04-07 8:33 ` Jie Gan
0 siblings, 1 reply; 5+ messages in thread
From: Leo Yan @ 2026-04-07 8:10 UTC (permalink / raw)
To: Jie Gan
Cc: Suzuki K Poulose, Mike Leach, James Clark, Alexander Shishkin,
Tingwei Zhang, coresight, linux-arm-kernel, linux-kernel
On Tue, Apr 07, 2026 at 12:47:11PM +0800, Jie Gan wrote:
> Create the csdev_access struct only when a valid MMIO resource is
> available. In tpdm_probe(), base is uninitialized for static TPDM
> instances that lack an MMIO resource, causing csdev_access to be
> created with a garbage address and potentially leading to
> unexpected issues.
This patch itself is fine for me. However, I am wandering if this
is sufficient.
As mentioned "potentially leading to unexpected issues", can I
understand some code pieces access register with uninitialized base?
If so, you would also explictly add coresight_is_static_tpdm() to
prevent register access.
Thanks,
Leo
> Fixes: 14ae052f7947 ("coresight: tpdm: add static tpdm support")
> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
> ---
> drivers/hwtracing/coresight/coresight-tpdm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index 9b16f368a58b..eaf7210af648 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -1430,6 +1430,7 @@ static int tpdm_probe(struct device *dev, struct resource *res)
> if (ret)
> return ret;
>
> + desc.access = CSDEV_ACCESS_IOMEM(base);
> if (tpdm_has_dsb_dataset(drvdata))
> of_property_read_u32(drvdata->dev->of_node,
> "qcom,dsb-msrs-num", &drvdata->dsb_msr_num);
> @@ -1452,7 +1453,6 @@ static int tpdm_probe(struct device *dev, struct resource *res)
> desc.ops = &tpdm_cs_ops;
> desc.pdata = dev->platform_data;
> desc.dev = dev;
> - desc.access = CSDEV_ACCESS_IOMEM(base);
> if (res)
> desc.groups = tpdm_attr_grps;
> else
>
> ---
> base-commit: 816f193dd0d95246f208590924dd962b192def78
> change-id: 20260407-fix-potential-issue-in-tpdm-b07b44416051
>
> Best regards,
> --
> Jie Gan <jie.gan@oss.qualcomm.com>
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] coresight: tpdm: fix invalid MMIO access issue
2026-04-07 8:10 ` Leo Yan
@ 2026-04-07 8:33 ` Jie Gan
2026-04-07 10:35 ` Leo Yan
0 siblings, 1 reply; 5+ messages in thread
From: Jie Gan @ 2026-04-07 8:33 UTC (permalink / raw)
To: Leo Yan
Cc: Suzuki K Poulose, Mike Leach, James Clark, Alexander Shishkin,
Tingwei Zhang, coresight, linux-arm-kernel, linux-kernel
Hi Leo
On 4/7/2026 4:10 PM, Leo Yan wrote:
> On Tue, Apr 07, 2026 at 12:47:11PM +0800, Jie Gan wrote:
>> Create the csdev_access struct only when a valid MMIO resource is
>> available. In tpdm_probe(), base is uninitialized for static TPDM
>> instances that lack an MMIO resource, causing csdev_access to be
>> created with a garbage address and potentially leading to
>> unexpected issues.
>
> This patch itself is fine for me. However, I am wandering if this
> is sufficient.
>
> As mentioned "potentially leading to unexpected issues", can I
> understand some code pieces access register with uninitialized base?
> If so, you would also explictly add coresight_is_static_tpdm() to
> prevent register access.
>
Actually, we havent MMIO access for the static TPDM device, So no issues
are observed. The commit message here may be misleading. do I need
rephrase the commit message?
Thanks,
Jie
> Thanks,
> Leo
>
>> Fixes: 14ae052f7947 ("coresight: tpdm: add static tpdm support")
>> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
>> ---
>> drivers/hwtracing/coresight/coresight-tpdm.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
>> index 9b16f368a58b..eaf7210af648 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
>> @@ -1430,6 +1430,7 @@ static int tpdm_probe(struct device *dev, struct resource *res)
>> if (ret)
>> return ret;
>>
>> + desc.access = CSDEV_ACCESS_IOMEM(base);
>> if (tpdm_has_dsb_dataset(drvdata))
>> of_property_read_u32(drvdata->dev->of_node,
>> "qcom,dsb-msrs-num", &drvdata->dsb_msr_num);
>> @@ -1452,7 +1453,6 @@ static int tpdm_probe(struct device *dev, struct resource *res)
>> desc.ops = &tpdm_cs_ops;
>> desc.pdata = dev->platform_data;
>> desc.dev = dev;
>> - desc.access = CSDEV_ACCESS_IOMEM(base);
>> if (res)
>> desc.groups = tpdm_attr_grps;
>> else
>>
>> ---
>> base-commit: 816f193dd0d95246f208590924dd962b192def78
>> change-id: 20260407-fix-potential-issue-in-tpdm-b07b44416051
>>
>> Best regards,
>> --
>> Jie Gan <jie.gan@oss.qualcomm.com>
>>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] coresight: tpdm: fix invalid MMIO access issue
2026-04-07 8:33 ` Jie Gan
@ 2026-04-07 10:35 ` Leo Yan
2026-04-07 10:59 ` Jie Gan
0 siblings, 1 reply; 5+ messages in thread
From: Leo Yan @ 2026-04-07 10:35 UTC (permalink / raw)
To: Jie Gan
Cc: Suzuki K Poulose, Mike Leach, James Clark, Alexander Shishkin,
Tingwei Zhang, coresight, linux-arm-kernel, linux-kernel
Hi Jie,
On Tue, Apr 07, 2026 at 04:33:22PM +0800, Jie Gan wrote:
> On 4/7/2026 4:10 PM, Leo Yan wrote:
> > On Tue, Apr 07, 2026 at 12:47:11PM +0800, Jie Gan wrote:
> > > Create the csdev_access struct only when a valid MMIO resource is
> > > available. In tpdm_probe(), base is uninitialized for static TPDM
> > > instances that lack an MMIO resource, causing csdev_access to be
> > > created with a garbage address and potentially leading to
> > > unexpected issues.
> >
> > This patch itself is fine for me. However, I am wandering if this
> > is sufficient.
> >
> > As mentioned "potentially leading to unexpected issues", can I
> > understand some code pieces access register with uninitialized base?
> > If so, you would also explictly add coresight_is_static_tpdm() to
> > prevent register access.
> >
>
> Actually, we havent MMIO access for the static TPDM device, So no issues are
> observed. The commit message here may be misleading. do I need rephrase the
> commit message?
Yes, good to clarify a bit in commit log:
"So far there has no register access for static instance, but this
change helps mitigate potential risks in the future."
With this:
Reviewed-by: Leo Yan <leo.yan@arm.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] coresight: tpdm: fix invalid MMIO access issue
2026-04-07 10:35 ` Leo Yan
@ 2026-04-07 10:59 ` Jie Gan
0 siblings, 0 replies; 5+ messages in thread
From: Jie Gan @ 2026-04-07 10:59 UTC (permalink / raw)
To: Leo Yan
Cc: Suzuki K Poulose, Mike Leach, James Clark, Alexander Shishkin,
Tingwei Zhang, coresight, linux-arm-kernel, linux-kernel
Hi Leo,
On 4/7/2026 6:35 PM, Leo Yan wrote:
> Hi Jie,
>
> On Tue, Apr 07, 2026 at 04:33:22PM +0800, Jie Gan wrote:
>> On 4/7/2026 4:10 PM, Leo Yan wrote:
>>> On Tue, Apr 07, 2026 at 12:47:11PM +0800, Jie Gan wrote:
>>>> Create the csdev_access struct only when a valid MMIO resource is
>>>> available. In tpdm_probe(), base is uninitialized for static TPDM
>>>> instances that lack an MMIO resource, causing csdev_access to be
>>>> created with a garbage address and potentially leading to
>>>> unexpected issues.
>>>
>>> This patch itself is fine for me. However, I am wandering if this
>>> is sufficient.
>>>
>>> As mentioned "potentially leading to unexpected issues", can I
>>> understand some code pieces access register with uninitialized base?
>>> If so, you would also explictly add coresight_is_static_tpdm() to
>>> prevent register access.
>>>
>>
>> Actually, we havent MMIO access for the static TPDM device, So no issues are
>> observed. The commit message here may be misleading. do I need rephrase the
>> commit message?
>
> Yes, good to clarify a bit in commit log:
>
> "So far there has no register access for static instance, but this
> change helps mitigate potential risks in the future."
>
> With this:
>
> Reviewed-by: Leo Yan <leo.yan@arm.com>
Well noted.
Thanks,
Jie
^ permalink raw reply [flat|nested] 5+ messages in thread
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2026-04-07 4:47 [PATCH] coresight: tpdm: fix invalid MMIO access issue Jie Gan
2026-04-07 8:10 ` Leo Yan
2026-04-07 8:33 ` Jie Gan
2026-04-07 10:35 ` Leo Yan
2026-04-07 10:59 ` Jie Gan
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