Subject: Re: [RFC] globmatch() helper function
From: Peter Zijlstra <peterz@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <srostedt@redhat.com>, George Spelvin <linux@horizon.com>,
        andi@firstfloor.org, linux-kernel@vger.kernel.org
In-Reply-To: <494929E5.8060302@kernel.org>
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	 <494929E5.8060302@kernel.org>
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Date: Wed, 17 Dec 2008 17:36:04 +0100
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On Thu, 2008-12-18 at 01:33 +0900, Tejun Heo wrote:
> Steven Rostedt wrote:
> > On Thu, 2008-12-18 at 01:22 +0900, Tejun Heo wrote:
> >> Hello,
> >>
> >> George Spelvin wrote:
> >>> Do people think that would be, on balance, better?  It would be plenty
> >>> good enough for the blacklist application.
> >> Just pass a depth parameter and trigger WARN_ON() and return -EINVAL
> >> when it exceeds ten.  It's a five minute change and should be enough
> >> for kernel usages.
> > 
> > If this is ever expected to be used by userspace, I would not include
> > the WARN_ON. If this is a generic function, then I'll include in in
> > ftrace as well, and that takes userspace input. The last thing I want is
> > a DoS because of printk's to the serial console because some userspace
> > app is constantly writing bad patterns to this file.
> 
> Well, then, how about printk_ratelimit()?  Having one too many
> asterisk will be a very rare occasion and when it happens it's
> something which can easily escape attention, so I think some form of
> whining is in order.

having the write fail with -EINVAL seems suitably whiney..

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