linux-kernel - Re: [Outreachy kernel] [PATCH 4/4] staging: rtl8723bs: Change the type and use of a variable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sat, 10 Apr 2021 15:55:49 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Cc:     Julia Lawall <julia.lawall@...ia.fr>,
        outreachy-kernel@...glegroups.com, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [Outreachy kernel] [PATCH 4/4] staging: rtl8723bs: Change the
 type and use of a variable

On Sat, Apr 10, 2021 at 03:53:38PM +0200, Fabio M. De Francesco wrote:
> On Saturday, April 10, 2021 3:24:43 PM CEST Julia Lawall wrote:
> > On Sat, 10 Apr 2021, Fabio M. De Francesco wrote:
> > > On Saturday, April 10, 2021 2:12:28 PM CEST Julia Lawall wrote:
> > > > On Sat, 10 Apr 2021, Fabio M. De Francesco wrote:
> > > > > On Saturday, April 10, 2021 1:37:30 PM CEST Julia Lawall wrote:
> > > > > > > That variable has global scope and is assigned at least in:
> > > > > > What do you mean by global scope?  None of the following look
> > > > > > like
> > > > > > references to global variables.
> > > > > > 
> > > > > > julia
> > > > > 
> > > > > I just mean that fw_current_in_ps_mode is a field of a struct in a
> > > > > .h
> > > > > file included everywhere in this driver and that the functions whom
> > > > > the following assignments belong to have not the "static" type
> > > > > modifier.
> > > > 
> > > > OK, but a field in a structure is not a variable, and this is not
> > > > what
> > > > scope means.
> > > 
> > > You're right, a field in a structure is not a variable.
> > > 
> > > > int x;
> > > > 
> > > > outside of anything is a global variable (global scope).
> > > > 
> > > > int foo() {
> > > > 
> > > >   int x;
> > > >   ...
> > > > 
> > > > }
> > > > 
> > > > Here x is a local variable.  Its scope is the body of the function.
> > > > 
> > > > int foo() {
> > > > 
> > > >   if (abc) {
> > > >   
> > > >     int x;
> > > >     ...
> > > >   
> > > >   }
> > > > 
> > > > }
> > > > 
> > > > Here x is a local variable, but its scope is only in the if branch.
> > > 
> > > And you're right again: I needed a little refresh of my knowledge of C.
> > > 
> > > I've searched again in the code for the purpose of finding out if that
> > > struct is initialized with global scope but I didn't find anything. I
> > > didn't even find any dynamic allocation within functions that returns
> > > pointers to that struct.
> > > 
> > > Therefore, according to Greg's request, I'll delete that stupid 'if'
> > > statement in the patch series v2 that I'm about to submit.
> > 
> > I'm really not clear on why the if should be deleted.
> > 
> > julia
> >
> I'm supposed to delete it because of the review made by Greg. In a couple 
> of previous messages he wrote:
> 
> "If this is only checked, how can it ever be true?  Who ever sets this 
> value?"
> 
> and then:
> 
> "Just delete the variable from the structure entirely and when it is
> used.".
> 
> However, like you, I'm not sure yet.

I don't think any of us are, try fixing up what you think is right and
resend and we can go from there :)