From 037067a1b6f9a70f862f3ed9d59fe28b7cd55ac4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 7 Aug 2011 20:26:31 -0700 Subject: [PATCH] rcu: Prohibit grace periods during early boot Greater use of RCU during early boot (before the scheduler is operating) is causing RCU to attempt to start grace periods during that time, which in turn is resulting in both RCU and the callback functions attempting to use the scheduler before it is ready. This commit prevents these problems by prohibiting RCU grace periods until after the scheduler has spawned the first non-idle task. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 0051dbf6958..9970116163b 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -838,8 +838,11 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) struct rcu_data *rdp = this_cpu_ptr(rsp->rda); struct rcu_node *rnp = rcu_get_root(rsp); - if (!cpu_needs_another_gp(rsp, rdp) || rsp->fqs_active) { - if (cpu_needs_another_gp(rsp, rdp)) + if (!rcu_scheduler_fully_active || + !cpu_needs_another_gp(rsp, rdp) || + rsp->fqs_active) { + if (rcu_scheduler_fully_active && + cpu_needs_another_gp(rsp, rdp)) rsp->fqs_need_gp = 1; if (rnp->completed == rsp->completed) { raw_spin_unlock_irqrestore(&rnp->lock, flags);