Re: [PATCH v4 0/8] coresight: Fix device registration and unregistration

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 24/02/2026 11:06, Leo Yan wrote:
> On Mon, Feb 23, 2026 at 01:28:03PM +0000, Suzuki K Poulose wrote:
> 
> [...]
> 
>> [  827.216924]  Possible unsafe locking scenario:
>> [  827.216924]
>> [  827.222849]        CPU0                    CPU1
>> [  827.227380]        ----                    ----
>> [  827.231912]   lock(coresight_mutex);
>> [  827.235491]                                lock(ect_mutex);
>> [  827.241073]                                lock(coresight_mutex);
>> [  827.247176]   lock(ect_mutex);
>> [  827.250233]
>> [  827.250233]  *** DEADLOCK ***
> 
> Thanks for the test, Suzuki.
> 
> I have sent a refactor patch to dismiss locking chain:
> https://lore.kernel.org/linux-arm-kernel/20260224-arm_coresight_refactor_cti_resource_release-v1-1-ff1b2bca9176@arm.com/T/#u
> 
> For recording, I enabled the following configs to reproduce the lockdep
> report:
> 

Thanks for the patch, I can confirm that it fixes the problem and is
indeed a good cleanup. Hacking the device release operation wasn't
really a good idea.

Cheers
Suzuki



>    CONFIG_LOCKUP_DETECTOR
>    CONFIG_PROVE_LOCKING
> 
> Thanks,
> Leo