Re: [PATCH v10 2/5] sched: CGroup tagging interface for core scheduling

[Josh Don]

On Fri, Feb 26, 2021 at 12:08 PM Chris Hyser <chris.hyser@xxxxxxxxxx> wrote:
>
> Update:
>
> The clone syscall stress test I have is causing a deadlock with this patchset when
> compiled with CONFIG_PROVE_RAW_LOCK_NESTING=y. I am able to get stacktraces with
> nmi_watchdog and am looking through those. Josh was not able to duplicate the
> deadlock, instead getting an actual warning about kmalloc w/GFP_ATOMIC while
> under a raw spinlock in the function __sched_core_update_cookie(). When I retry
> the test with a patch Josh sent, removing the kmalloc() and thus the trigger of
> the warning, no more deadlock. So some combination of CONFIGs, timing and
> function calls seems to have found something in this LOCK proving code.
>
> -chrish

I have a patch to remove the dynamic allocation and overall simplify
the logic here. Will squash that along with the rest of the
modifications suggested by Peter in the next version.