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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 12 Oct 2021 23:58:50 +0300
Message-ID: <CAHp75Vdx1=q=5sNkn9o=mqnufxYiXnssmMJtXw9goFskGijc1w@mail.gmail.com>
Subject: Re: [PATCH] iio: buffer: Fix double-free in iio_buffers_alloc_sysfs_and_mask()
To:     Joe Perches <joe@perches.com>
Cc:     Alexandru Ardelean <ardeleanalex@gmail.com>,
        Yang Yingliang <yangyingliang@huawei.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Jonathan Cameron <jic23@kernel.org>
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On Tue, Oct 12, 2021 at 8:55 PM Joe Perches <joe@perches.com> wrote:
> On Tue, 2021-10-12 at 23:48 +0300, Andy Shevchenko wrote:
> > On Tue, Oct 12, 2021 at 8:43 PM Joe Perches <joe@perches.com> wrote:
> > > On Tue, 2021-10-12 at 23:30 +0300, Andy Shevchenko wrote:
> > > > On Tue, Oct 12, 2021 at 2:37 PM Alexandru Ardelean
> > > > <ardeleanalex@gmail.com> wrote:
> > > > > On Tue, Oct 12, 2021 at 12:18 PM Yang Yingliang
> > > > > <yangyingliang@huawei.com> wrote:

...

> > > > I prefer to see
> > > >
> > > > - for (; unwind_idx >= 0; unwind_idx--) {
> > > > + while (unwind_idx--)
> > >
> > > Not the same code as unwind_idx would be decremented before entering
> > > the code block.
> >
> > It's kinda cryptic what you are pointing out.
>
> Not really,

It's. It lacks the very same "additional" words to explain what you
meant and why.

> > What's needed additionally is to change
> >
> > - unwind_idx = iio_dev_opaque->attached_buffers_cnt - 1;
> > + unwind_idx = i;
>
> You left out that 'additional change' above from your reply.

Yes, that's true, but it took some time to decrypt your message.

> > Of course not. See above. The usual pattern is
> >
> >   while (i--)
> >     do_clean_item(i);
>
> Of course, but that's not what you replied.
> I was merely pointing out that your reply included a logic change
> converting a loop from for to while.

I expect that developers actually think about the changes they do and
double check what's proposed by reviewers. If they just copy'n'paste
whatever others propose, I wouldn't take any patch from such a
developer.

-- 
With Best Regards,
Andy Shevchenko