Messages in this thread | | | Subject | Re: scheduler problems in -next (was: Re: [PATCH 6.4 000/227] 6.4.7-rc1 review) | From | Roy Hopkins <> | Date | Wed, 02 Aug 2023 14:57:56 +0100 |
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On Tue, 2023-08-01 at 12:11 -0700, Paul E. McKenney wrote: > On Tue, Aug 01, 2023 at 10:32:45AM -0700, Guenter Roeck wrote: > > > Please see below for my preferred fix. Does this work for you guys? > > Back to figuring out why recent kernels occasionally to blow up all > rcutorture guest OSes... > > Thanx, Paul > > ------------------------------------------------------------------------ > > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h > index 7294be62727b..2d5b8385c357 100644 > --- a/kernel/rcu/tasks.h > +++ b/kernel/rcu/tasks.h > @@ -570,10 +570,12 @@ static void rcu_tasks_one_gp(struct rcu_tasks *rtp, bool midboot) > if (unlikely(midboot)) { > needgpcb = 0x2; > } else { > + mutex_unlock(&rtp->tasks_gp_mutex); > set_tasks_gp_state(rtp, RTGS_WAIT_CBS); > rcuwait_wait_event(&rtp->cbs_wait, > (needgpcb = rcu_tasks_need_gpcb(rtp)), > TASK_IDLE); > + mutex_lock(&rtp->tasks_gp_mutex); > } > > if (needgpcb & 0x2) {
Your preferred fix looks good to me.
With the original code I can quite easily reproduce the problem on my system every 10 reboots or so. With your fix in place the problem no longer occurs.
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