Re: [1/4] rcu: Detect uses of rcu read side in extended quiescent states

Milton Miller
2011-06-06T03:44:36Z

On Mon, 06 Jun 2011 about 03:10:55 -0000, Frederic Weisbecker wrote:
> @@ -3994,8 +3995,13 @@ void lockdep_rcu_dereference(const char *file, const int line)
> printk("\n===================================================\n");
> printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n");
> printk( "---------------------------------------------------\n");
> - printk("%s:%d invoked rcu_dereference_check() without protection!\n",
> - file, line);
> + printk("%s:%d invoked rcu_dereference_check() ", file, line);
> +
> + if (type == RCU_WARN_UNPROTECTED)
> + printk("without protection!\n");
> + else if (type == RCU_WARN_EXT_QS)
> + printk("while in RCU extended quiescent state!\n");
> +
> printk("\nother info that might help us debug this:\n\n");
> printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks);
> lockdep_print_held_locks(curr);

Can we keep the above in one printk? That way the printing is
guaranteed to come out on one line. Probably the easiest way would
be add char *why = "" then assign a string based on the current
conditions. Do all of that before the first printk which gets the
a %s added.

Thanks,
milton