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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130424064813.GB27551@gmail.com>
Date:	Wed, 24 Apr 2013 08:48:13 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Dave Jones <davej@...hat.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...e.hu>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: Print out additional debugging advice when we hit lockdep BUGs


* Dave Jones <davej@...hat.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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/