Re: [PATCH] usb: gadget: uvc: Fix ERR_PTR dereference in uvc_v4l2.c

[Abhishek Tamboli <abhishektamboli9@gmail.com>]

On Fri, Aug 02, 2024 at 01:40:48PM -0500, Dan Carpenter wrote:
> On Fri, Aug 02, 2024 at 11:32:47PM +0530, Abhishek Tamboli wrote:
> > Fix potential dereferencing of ERR_PTR() in find_format_by_pix()
> > and uvc_v4l2_enum_format().
> > 
> > Fix the following smatch errors:
> > 
> > drivers/usb/gadget/function/uvc_v4l2.c:124 find_format_by_pix()
> > error: 'fmtdesc' dereferencing possible ERR_PTR()
> > drivers/usb/gadget/function/uvc_v4l2.c:392 uvc_v4l2_enum_format()
> > error: 'fmtdesc' dereferencing possible ERR_PTR()
> > 
> > Signed-off-by: Abhishek Tamboli <abhishektamboli9@gmail.com>
> 
> When I reviewed these warnings in 2022, I assumed that the error
> checking was left out deliberately because it couldn't fail so I didn't
> report these warnings.
> 
> Almost all old Smatch warnings are false positives.  That doesn't mean
> Smatch is bad, it's just how it's going to be when you fix all the real
> bugs.  In this case, I just decided it was a false positive.  It's
> possible I was wrong.  Other times, I report the bug and the maintainers
> say that it's a false positive.
> 
> There are some old bugs which are real.  Sometimes I report a bug but
> the maintainer doesn't see the email because they go on vacation or
> something.  Or someone sends a patch but it doesn't get merged.  Another
> thing is that if a bug is over five years old and minor then I might not
> bother reporting it.  These days kernel developers are very good at
> fixing static checker bugs and these kinds of things are pretty rare.
> 
> I don't review old warnings in a systematic way.  If I fix a bug in a
> file, then I'll re-review all the old warnings.
> 
> If we decide to merge this code, it needs a Fixes tag.
> 
Hi,

I wanted to follow up on the patch I submitted to address a Smatch warning.
While I understand that this warning might be a false positive, as mentioned in your
reviews, I would greatly appreciate your guidance on whether this patch should be
merged or if any further adjustments are needed.

If we determine that the patch resolves a real issue, I am prepared to
include the Fixes tag.

Regards,
Abhishek