Re: [PATCH 2/2] debugfs: return error values, not NULL

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Jan 23, 2019 at 11:29:30AM +0100, Greg Kroah-Hartman wrote:
> On Wed, Jan 23, 2019 at 11:28:14AM +0100, Greg Kroah-Hartman wrote:
> > When an error happens, debugfs should return an error pointer value, not
> > NULL.  This will prevent the totally theoretical error where a debugfs
> > call fails due to lack of memory, returning NULL, and that dentry value
> > is then passed to another debugfs call, which would end up succeeding,
> > creating a file at the root of the debugfs tree, but would then be
> > impossible to remove (because you can not remove the directory NULL).
> > 
> > So, to make everyone happy, always return errors, this makes the users
> > of debugfs much simpler (they do not have to ever check the return
> > value), and everyone can rest easy.
> > 
> > Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
> > Reported-by: Gary R Hook <ghook@amd.com>
> > Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
> 
> Oops, also reported by:
> 	Sebastian Andrzej Siewior <bigeasy@linutronix.de>

And also reported by:
	Michal Hocko <mhocko@kernel.org>

I should have checked my inbox better...