Re: [PATCH] iio: buffer: Fix double-free in iio_buffers_alloc_sysfs_and_mask()

[Joe Perches <joe@xxxxxxxxxxx>]

On Tue, 2021-10-12 at 23:30 +0300, Andy Shevchenko wrote:
> On Tue, Oct 12, 2021 at 2:37 PM Alexandru Ardelean
> <ardeleanalex@xxxxxxxxx> wrote:
> > 
> > On Tue, Oct 12, 2021 at 12:18 PM Yang Yingliang
> > <yangyingliang@xxxxxxxxxx> wrote:
> > > 
> > > When __iio_buffer_alloc_sysfs_and_mask() failed, 'unwind_idx' should be
> > > set to 'i - 1' to prevent double-free when cleanup resources.
[]
> 
> 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.

You'd want

	do {
		...
	} while (unwind_idx--);