Re: resctrl mount fail on v6.13-rc1

[Fenghua Yu]

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