Re: [Intel-wired-lan] [RFT net-next PATCH RESEND 0/2] ethernet: intel: fix freeing uninitialized pointers with __free

[ally heev <allyheev@gmail.com>]

On Wed, 2025-12-03 at 09:45 +0100, Przemek Kitszel wrote:
> On 12/3/25 09:09, ally heev wrote:
> > On Tue, 2025-12-02 at 10:17 -0800, Tony Nguyen wrote:
> > > 
> > > On 12/2/2025 11:47 AM, ally heev wrote:
> > > > On Mon, 2025-12-01 at 13:40 -0800, Tony Nguyen wrote:
> > > > > 
> > > > > On 11/23/2025 11:40 PM, Ally Heev wrote:
> > > > > > Uninitialized pointers with `__free` attribute can cause undefined
> > > > > > behavior as the memory assigned randomly to the pointer is freed
> > > > > > automatically when the pointer goes out of scope.
> > > > > > 
> > > > > > We could just fix it by initializing the pointer to NULL, but, as usage of
> > > > > > cleanup attributes is discouraged in net [1], trying to achieve cleanup
> > > > > > using goto
> > > > > 
> > > > > These two drivers already have multiple other usages of this. All the
> > > > > other instances initialize to NULL; I'd prefer to see this do the same
> > > > > over changing this single instance.
> > > > > 
> > > > 
> > > > Other usages are slightly complicated to be refactored and might need
> > > > good testing. Do you want me to do it in a different series?
> > > 
> > > Hi Ally,
> > > 
> > > Sorry, I think I was unclear. I'd prefer these two initialized to NULL,
> > > to match the other usages, over removing the __free() from them.
> > 
> > I had a patch for that already, but, isn't using __free discouraged in
> > networking drivers [1]? Simon was against it [2]
> 
> you see, the construct is discouraged, so we don't use it everywhere,
> but cleaning up just a little would not change the state of the matter
> (IOW we will still be in "driver has some __free() usage" state).
> 

But still we can just fix the uninitialized ones the right way [1]
right? since we have to fix them anyway. There already a patch [2] for
that

[1]
https://lore.kernel.org/lkml/CAHk-=wiCOTW5UftUrAnvJkr6769D29tF7Of79gUjdQHS_TkF5A@mail.gmail.com/
[2]
https://lore.kernel.org/all/20251106-aheev-uninitialized-free-attr-net-ethernet-v3-1-ef2220f4f476@gmail.com/

> TBH, I would not spent my time "undoing" all of the __free() that we
> have already, especially the testing part sounds not fun.

+1

> 
> Turning all usage points to "= NULL" is orthogonal, and would be great.
> 
> > 
> > [2] https://lore.kernel.org/all/aQ9xp9pchMwml30P@horms.kernel.org/
> > [1] https://docs.kernel.org/process/maintainer-netdev.html#using-device-managed-and-cleanup-h-constructs
> > 
> > Regards,
> > Ally
> >