linux-kernel - Re: resctrl mount fail on v6.13-rc1

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Message-ID: <fb8d4e7f-2704-265d-65a9-1e3e37b5fca8@intel.com>
Date: Mon, 2 Dec 2024 14:46:58 -0800
From: Fenghua Yu <fenghua.yu@...el.com>
To: Reinette Chatre <reinette.chatre@...el.com>, "Luck, Tony"
	<tony.luck@...el.com>, Peter Newman <peternewman@...gle.com>, Babu Moger
	<babu.moger@....com>
CC: <linux-kernel@...r.kernel.org>
Subject: Re: resctrl mount fail on v6.13-rc1

Hi, Tony and Reinette,

On 12/2/24 14:26, Reinette Chatre wrote:
> Hi Tony,
> 
> On 12/2/24 1:42 PM, Luck, Tony wrote:
>> Anyone better a decoding lockdep dumps then me make sense of this?
>>
>> All I did was build v6.13-rc1 with (among others)
>>
>> CONFIG_PROVE_LOCKING=y
>> CONFIG_PROVE_RAW_LOCK_NESTING=y
>> CONFIG_PROVE_RCU=y
>>
>> and then mount the resctrl filesystem:
>>
>> $ sudo mount -t resctrl resctrl /sys/fs/resctrl
>>
>> There are only trivial changes to the resctrl code between
>> v6.12 (which works) and v6.13-rc1:
>>
>> $ git log --oneline v6.13-rc1 ^v6.12 -- arch/x86/kernel/cpu/resctrl
>> 5a4b3fbb4849 Merge tag 'x86_cache_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
>> 9bce6e94c4b3 x86/resctrl: Support Sub-NUMA cluster mode SNC6
>> 29eaa7958367 x86/resctrl: Slightly clean-up mbm_config_show()
>>
>> So something in kernfs? Or the way resctrl uses kernfs?
> 
> I am not seeing this but that may be because I am not testing with
> selinux enabled. My test kernel has:
> # CONFIG_SECURITY_SELINUX is not set
> 
> I am also not running with any btrfs filesystems.
> 
> Is this your usual setup in which you are seeing this the first time? Is it
> perhaps possible for you to bisect?
> 
> The subject states "resctrl mount fail" - could you please confirm if
> resctrl cannot be mounted in addition to the lockdep warning?
> 
> Reinette
> 

I can reproduce the issue with
CONFIG_PROVE_LOCKING=y
CONFIG_PROVE_RAW_LOCK_NESTING=y
CONFIG_PROVE_RCU=y
and SELINUX enabled.

Thanks.

-Fenghua