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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Joe Perches <joe@perches.com>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>,
	Jonathan Corbet <corbet@lwn.net>,
	Saravana Kannan <saravanak@google.com>,
	Jason Baron <jbaron@akamai.com>, Will Deacon <will@kernel.org>,
	linux-kernel@vger.kernel.org, kernel-team@android.com,
	Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH v5] dynamic_debug: allow to work if debugfs is disabled
Date: Sun, 9 Feb 2020 18:03:54 +0100	[thread overview]
Message-ID: <20200209170354.GA3171@kroah.com> (raw)
In-Reply-To: <c6db92330696e0e1145103b4e59bf30a982f5e4b.camel@perches.com>

On Sun, Feb 09, 2020 at 07:53:38AM -0800, Joe Perches wrote:
> On Sun, 2020-02-09 at 12:05 +0100, Greg Kroah-Hartman wrote:
> > With the realization that having debugfs enabled on "production" systems
> > is generally not a good idea, debugfs is being disabled from more and
> > more platforms over time.  However, the functionality of dynamic
> > debugging still is needed at times, and since it relies on debugfs for
> > its user api, having debugfs disabled also forces dynamic debug to be
> > disabled.
> > 
> > To get around this, also create the "control" file for dynamic_debug in
> > procfs.  This allows people turn on debugging as needed at runtime for
> > individual driverfs and subsystems.
> > 
> > Reported-by: many different companies
> > Cc: Jason Baron <jbaron@akamai.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> > v5: as many people asked for it, now enable the control file in both
> >     debugfs and procfs at the same time.
> 
> So now there can be differences in the two control files
> and these are readable files are sometimes parsed by
> scripts.

What difference will there be?  They should both be the same, as they
point to the identical fops behind the virtual file.

> It'd be better to figure out how to soft link the files.

A symlink is not going to work, but this should be fine from what I can
tell.  I'll do some more debugging tonight, but all was fine last I
tried this last week.

thanks,

greg k-h

  reply	other threads:[~2020-02-09 17:22 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-22  7:43 [PATCH] dynamic_debug: allow to work if debugfs is disabled Greg Kroah-Hartman
2020-01-22  8:03 ` Will Deacon
2020-01-22  8:12   ` Greg Kroah-Hartman
2020-01-22 13:53     ` [PATCH v2] " Greg Kroah-Hartman
2020-01-22 18:56       ` Jason Baron
2020-01-22 19:29         ` Greg Kroah-Hartman
2020-01-22 19:31           ` [PATCH v3] " Greg Kroah-Hartman
2020-01-22 21:43             ` Randy Dunlap
2020-01-23  8:48               ` Greg Kroah-Hartman
2020-01-23  8:50                 ` [PATCH v4] " Greg Kroah-Hartman
2020-01-23  9:36                   ` Will Deacon
2020-01-23 15:53             ` [PATCH v3] " Theodore Y. Ts'o
2020-01-23 17:55               ` Greg Kroah-Hartman
2020-01-24  6:02                 ` Theodore Y. Ts'o
2020-01-24  7:29                   ` Greg Kroah-Hartman
2020-01-25  1:42                     ` Theodore Y. Ts'o
2020-01-25 17:11                       ` Jonathan Corbet
2020-01-27 22:19                         ` Saravana Kannan
2020-02-09 11:05               ` [PATCH v5] " Greg Kroah-Hartman
2020-02-09 15:53                 ` Joe Perches
2020-02-09 17:03                   ` Greg Kroah-Hartman [this message]
2020-02-10 21:11                 ` [PATCH v6] " Greg Kroah-Hartman
2020-02-10 21:15                   ` Randy Dunlap
2020-02-12 21:58                     ` Greg Kroah-Hartman
2020-02-11 11:01                   ` Will Deacon
2020-01-25  0:03 ` [PATCH] " kbuild test robot

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