[PATCH] rcu: fix hotplug-cpu ->donelist leak

Pointed out by Srivatsa Vaddagiri <vatsa@in.ibm.com>.

rcu_do_batch() stops after processing maxbatch callbacks
on ->donelist leaving rcu_tasklet in TASKLET_STATE_SCHED
state.

If CPU_DEAD event happens remaining ->donelist entries are
lost, rcu_offline_cpu() kills this tasklet.

With this patch ->donelist migrates along with ->curlist
and ->nxtlist to the current cpu.

Compile tested.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Paul E. McKenney <paulmck@us.ibm.com>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index e18f9190eafa112a9a1b08b25a608ab4dcb733cd..0cf8146bd58595b4115d07b39cdb866695a3b601 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -343,8 +343,9 @@ static void __rcu_offline_cpu(struct rcu_data *this_rdp,
        spin_unlock_bh(&rcp->lock);
        rcu_move_batch(this_rdp, rdp->curlist, rdp->curtail);
        rcu_move_batch(this_rdp, rdp->nxtlist, rdp->nxttail);
-
+       rcu_move_batch(this_rdp, rdp->donelist, rdp->donetail);
 }
+
 static void rcu_offline_cpu(int cpu)
 {
        struct rcu_data *this_rdp = &get_cpu_var(rcu_data);