If p->mountpoint is "/", off will be 0 and we will
try to acess path[-1].

 On Tue, Sep 20, 2016 at 05:17:27PM +0300, Kirill Tkhai wrote:
> >
> > int off = 0;
> >
> > ...
> >
> > if (p->mountpoint[1] != 0) /* not / */
> >    off = snprintf(path, len, %s, p->mountpoint);
> > if (path[off - 1] == '/') /* p->mountpoint = ./ */
> >
> >          ^^^
> > The above looks like off-by-one when off == 0. Is there is
> > a condition which guarantees that off is not zero?

travis-ci: success for mount: skip '/' only if it is there
Reported-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>