Re: [7.1-rc1 BUG] System hang when reading clock controller sysfs 'registers' files

[Krzysztof Kozlowski]

On 04/05/2026 09:49, Konrad Dybcio wrote:
> On 5/2/26 8:40 AM, Daniel J Blueman wrote:
>> On a Qualcomm X1 Hamoa-based Lenovo Slim7x with upstream 7.1-rc1, when
>> reading any of the /sys/kernel/debug/regmap/*clock*/registers files
>> [1] (which could happen inadvertently with grep), we see a complete
>> and immediate system hang.
>>
>> If this relates to clock/power gating, it could be avoided by
>> inhibiting that prior to the read. It also reproduces when booted with
>> "clk_ignore_unused pd_ignore_unused".
> 
> Does this attempt to read the entire regmap-ped address space of the
> device?
> 
> If so, that's probably ""intended"", since there are TZ-only (and other
> forms of secure) registers sprinkled throughout the range

Yep. See also commit d81901a5406e ("clk: qcom: dispcc-sm8750: Allow
dumping regmap").

We might need something similar for all other devices.

Best regards,
Krzysztof