Re: [PATCH RT v2 1/3] rcu: Acquire RCU lock when disabling BHs
From: Sebastian Andrzej Siewior
Date: Mon Aug 26 2019 - 11:59:48 EST
On 2019-08-23 14:46:39 [-0500], Scott Wood wrote:
> > > Before consolidation, RT mapped rcu_read_lock_bh_held() to
> > > rcu_read_lock_bh() and called rcu_read_lock() from
> > > rcu_read_lock_bh(). This
> > > somehow got lost when rebasing on top of 5.0.
> > so now rcu_read_lock_bh_held() is untouched and in_softirq() reports 1.
> > So the problem is that we never hold RCU but report 1 like we do?
I understand the part where "rcu_read_lock() becomes part of
local_bh_disable()". But why do you modify rcu_read_lock_bh_held() and
rcu_read_lock_bh()? Couldn't they remain as-is?