linux-kernel - Re: [PATCH] Support resetting WARN*

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Date:   Thu, 19 Oct 2017 13:47:06 -0700
From:   Andi Kleen <ak@...ux.intel.com>
To:     Michael Ellerman <mpe@...erman.id.au>
Cc:     Andi Kleen <andi@...stfloor.org>, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Support resetting WARN*_ONCE

On Wed, Oct 18, 2017 at 04:35:14PM +1100, Michael Ellerman wrote:
> Andi Kleen <andi@...stfloor.org> writes:
> 
> > From: Andi Kleen <ak@...ux.intel.com>
> >
> > I like _ONCE warnings because it's guaranteed that they don't
> > flood the log.
> >
> > During testing I find it useful to reset the state of the once warnings,
> > so that I can rerun tests and see if they trigger again, or can
> > guarantee that a test run always hits the same warnings.
> >
> > This patch adds a debugfs interface to reset all the _ONCE
> > warnings so that they appear again:
> >
> > echo 1 > /sys/kernel/debug/clear_warn_once
> >
> > This is implemented by putting all the warning booleans into
> > a special section, and clearing it.
> 
> That won't work for arches that do the ONCE logic with a flag will it?
> ie. arm64, parisc, powerpc, s390, sh, x86.

Thanks. I sent an incremential patch that fixes this.

-Andi