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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lkdtm: no need to check return value of debugfs_create functions
Date: Tue, 11 Jun 2019 20:56:56 +0200	[thread overview]
Message-ID: <20190611185656.GB4659@kroah.com> (raw)
In-Reply-To: <201906111144.3E05EAA80@keescook>

On Tue, Jun 11, 2019 at 11:44:53AM -0700, Kees Cook wrote:
> On Tue, Jun 11, 2019 at 08:32:13PM +0200, Greg Kroah-Hartman wrote:
> > When calling debugfs functions, there is no need to ever check the
> > return value.  The function can work or not, but the code logic should
> > never do something different based on this.
> 
> What is the user-visible feedback when, say, debugfs_create_file()
> fails?

All of the memory in your system is now gone and it would have long
locked up a while before this call ever happened :)

And no user functionality should ever change if a debugfs call fails, or
succeeds, this is debugging only.

> And what happens when debugfs_create_file() passes in a NULL root?

The file ends up in the root of debugfs.  But as this can only happen if
the system is dead, I wouldn't worry about it.

thanks,

greg k-h

  reply	other threads:[~2019-06-11 18:57 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-11 18:32 [PATCH] lkdtm: no need to check return value of debugfs_create functions Greg Kroah-Hartman
2019-06-11 18:44 ` Kees Cook
2019-06-11 18:56   ` Greg Kroah-Hartman [this message]
2019-06-11 20:43 ` Kees Cook
2019-06-12 11:36   ` Greg Kroah-Hartman

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