linux-kernel - Re: [RFC PATCH 03/13] usb: remove the usage of the list iterator after the loop

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Date:   Mon, 28 Feb 2022 08:08:03 +0100
From:   Martin Uecker <uecker@...raz.at>
To:     Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 03/13] usb: remove the usage of the list iterator
 after the loop

Am Sonntag, den 27.02.2022, 19:12 +0100 schrieb Miguel Ojeda:
> On Sat, Feb 26, 2022 at 3:43 AM Martin Uecker <uecker@...raz.at> wrote:
> > Roughly the same group of people / companies that
> > write the compilers also control what goes into the
> > standard. They then like to point to the standard
> 
> Indeed, at least to a substantial degree.
> 
> > For signed overflow, I am not entirely sure what the
> > right choice is.  Wrapping for signed overflow also seems
> > dangerous. I use UBsan to find such issues in my code, and
> > this would not really work if signed overflow was defined
> > to wrap.
> 
> UBsan and similar tooling may still be used to find whatever behavior
> one wants, whether defined or not. UBSan already has non-UB checks.

Technically, this is true but not really in practice. If signed
overflow would be defined to wrap, then code would start to
rely on it and detecting it becomes useless because there are
too many false positives.  In your own small controlled code 
base it could work though.

Martin