Hi Paul,

On Thu, Jun 30, 2016 at 6:52 PM, Paul E. McKenney
[off-list ref] wrote:

On Thu, Jun 30, 2016 at 05:53:42PM +0200, Geert Uytterhoeven wrote:

quoted

+void rcu_dump_rcu_sched_tree(void)
+{
+     struct rcu_head rh;
+     unsigned long flags;
+
+     rcu_dump_rcu_node_tree(&rcu_sched_state);  /* Initial state. */
+     local_irq_save(flags);
+     // call_rcu(&rh, do_nothing_cb);
+     local_irq_restore(flags);
+     // schedule_timeout_uninterruptible(5 * HZ);  /* Or whatever delay. */
+     rcu_dump_rcu_node_tree(&rcu_sched_state); /* GP state. */
+     //synchronize_sched();  /* Probably hangs. */
+     //rcu_barrier();  /* Drop RCU's references to rh before return. */
+}

quoted

When enabling any of the 4 commented-out lines in rcu_dump_rcu_sched_tree(),
it will lock up.

OK, but that includes schedule_timeout_uninterruptible(5 * HZ), right?

Yes it does.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds