linux-kernel - Re: [PATCH] staging: vchiq_arm: Fix missing refcount decrement in error path for fw

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Message-ID: <2024101442-earthling-maverick-f591@gregkh>
Date: Mon, 14 Oct 2024 10:33:03 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Javier Carrasco <javier.carrasco.cruz@...il.com>
Cc: Dan Carpenter <dan.carpenter@...aro.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Stefan Wahren <wahrenst@....net>,
	Umang Jain <umang.jain@...asonboard.com>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-staging@...ts.linux.dev,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] staging: vchiq_arm: Fix missing refcount decrement in
 error path for fw_node

On Mon, Oct 14, 2024 at 10:15:25AM +0200, Javier Carrasco wrote:
> On 14/10/2024 10:12, Dan Carpenter wrote:
> > On Mon, Oct 14, 2024 at 09:59:49AM +0200, Javier Carrasco wrote:
> >> This approach is great as long as the maintainer accepts mid-scope
> >> variable declaration and the goto instructions get refactored, as stated
> >> in cleanup.h.
> >>
> >> The first point is not being that problematic so far, but the second one
> >> is trickier, and we all have to take special care to avoid such issues,
> >> even if they don't look dangerous in the current code, because adding a
> >> goto where there cleanup attribute is already used can be overlooked as
> >> well.
> >>
> > 
> > To be honest, I don't really understand this paragraph.  I think maybe you're
> > talking about if we declare the variable at the top and forget to initialize it
> > to NULL?  It leads to an uninitialized variable if we exit the function before
> > it is initialized.
> > 
> 
> No, I am talking about declaring the variable mid-scope, and later on
> adding a goto before that declaration in a different patch, let's say
> far above the variable declaration. As soon as a goto is added, care
> must be taken to make sure that we don't have variables with the cleanup
> attribute in the scope. Just something to take into account.

For this simple probe function, it's not an issue, please just make it
as simple and clean as possible.

thanks,

greg k-h