From f4579fc57cf4244057b713b1f73f4dc9f0b11e97 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 25 Jul 2014 11:21:47 -0700 Subject: rcu: Fix attempt to avoid unsolicited offloading of callbacks Commit b58cc46c5f6b (rcu: Don't offload callbacks unless specifically requested) failed to adjust the callback lists of the CPUs that are known to be no-CBs CPUs only because they are also nohz_full= CPUs. This failure can result in callbacks that are posted during early boot getting stranded on nxtlist for CPUs whose no-CBs property becomes apparent late, and there can also be spurious warnings about offline CPUs posting callbacks. This commit fixes these problems by adding an early-boot rcu_init_nohz() that properly initializes the no-CBs CPUs. Note that kernels built with CONFIG_RCU_NOCB_CPU_ALL=y or with CONFIG_RCU_NOCB_CPU=n do not exhibit this bug. Neither do kernels booted without the nohz_full= boot parameter. Signed-off-by: Paul E. McKenney Reviewed-by: Pranith Kumar Tested-by: Paul Gortmaker --- init/main.c | 1 + 1 file changed, 1 insertion(+) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index bb1aed928f21..e3c4cdd94d5b 100644 --- a/init/main.c +++ b/init/main.c @@ -578,6 +578,7 @@ asmlinkage __visible void __init start_kernel(void) idr_init_cache(); rcu_init(); tick_nohz_init(); + rcu_init_nohz(); context_tracking_init(); radix_tree_init(); /* init some links before init_ISA_irqs() */ -- cgit v1.2.3