Re: Print out additional debugging advice when we hit lockdep BUGs

[Ingo Molnar <mingo@kernel.org>]

* Dave Jones <davej@redhat.com> wrote:

> We occasionally get reports of these BUGs being hit, and the stack trace
> doesn't necessarily always tell us what we need to know about why we are
> hitting those limits.
> 
> If users start attaching /proc/lock_stats to reports we may have more of
> a clue what's going on.

Good idea.

A detail:

>  		printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
>  		printk("turning off the locking correctness validator.\n");
> +		printk("Attach output of /proc/lock_stat to bug report\n");

>  		printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
>  		printk("turning off the locking correctness validator.\n");
> +		printk("Attach output of /proc/lock_stat to bug report\n");

>  		printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
>  		printk("turning off the locking correctness validator.\n");
> +		printk("Attach output of /proc/lock_stat to bug report\n");

>  		printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
>  		printk("turning off the locking correctness validator.\n");
> +		printk("Attach output of /proc/lock_stat to bug report\n");

>  		printk("BUG: MAX_LOCK_DEPTH too low, depth: %i  max: %lu!\n",
>  		       curr->lockdep_depth, MAX_LOCK_DEPTH);
>  		printk("turning off the locking correctness validator.\n");
> +		printk("Attach output of /proc/lock_stat to bug report\n");

These patterns repeated in 4 places really call for a common helper 
defined as print_lockdep_off(fmt...) or so?

(Can be a followup patch if that's easier for you.)

Thanks,

	Ingo