Re: [RFC] Deadlock via recursive wakeup via RCU with threadirqs

From: Sebastian Andrzej Siewior
Date: Thu Jun 27 2019 - 11:40:19 EST

On 2019-06-27 11:37:10 [-0400], Joel Fernandes wrote:
> Sebastian it would be nice if possible to trace where the
> t->rcu_read_unlock_special is set for this scenario of calling
> rcu_read_unlock_special, to give a clear idea about whether it was
> really because of an IPI. I guess we could also add additional RCU
> debug fields to task_struct (just for debugging) to see where there
> unlock_special is set.
> Is there a test to reproduce this, or do I just boot an intel x86_64
> machine with "threadirqs" and run into it?

Do you want to send me a patch or should I send you my kvm image which
triggers the bug on boot?