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

[Peter Zijlstra]

On Mon, Feb 22, 2021 at 11:00:37PM -0500, Chris Hyser wrote:
> On 1/22/21 8:17 PM, Joel Fernandes (Google) wrote:
> While trying to test the new prctl() code I'm working on, I ran into a bug I
> chased back into this v10 code. Under a fair amount of stress, when the
> function __sched_core_update_cookie() is ultimately called from
> sched_core_fork(), the system deadlocks or otherwise non-visibly crashes.
> I've not had much success figuring out why/what. I'm running with LOCKDEP on
> and seeing no complaints. Duplicating it only requires setting a cookie on a
> task and forking a bunch of threads ... all of which then want to update
> their cookie.

Can you share the code and reproducer?