linux-kernel - Re: [PATCH] drivers/iommu: don't select DEBUG_FS for AMD_IOMMU

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Message-ID: <20160405224152.GK17838@8bytes.org>
Date:	Wed, 6 Apr 2016 00:41:52 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Paul Gortmaker <paul.gortmaker@...driver.com>,
	linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org
Subject: Re: [PATCH] drivers/iommu: don't select DEBUG_FS for AMD_IOMMU_STATS

On Tue, Apr 05, 2016 at 12:37:54PM -0400, Steven Rostedt wrote:
> I will argue that people have asked me to move tracing out of debugfs
> (which is why I created tracefs) because the problem with debugfs is
> that it opens up a entire system that is not well scrutinized, and
> holds lots of possible ways to crack the kernel.
> 
> Disabling debugfs does help with the "security" point you mentioned
> above.

Yes, that reasoning makes more sense than "debug features are bad for
production". It should've been part of the commit message.

The AMD_IOMMU_STATS feature is on my list of things to remove anyway, it
is mostly disabled and should be done differently (via per-device sysfs
stats). So I am just going to remove it for now.


	Joerg