Re: vfs: INFO: possible circular locking dependency detected

Al Viro
2012-05-09T16:28:58Z

On Wed, May 09, 2012 at 06:23:30PM +0200, Sasha Levin wrote:
> On Wed, May 9, 2012 at 6:12 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> > On Wed, May 09, 2012 at 05:25:14PM +0200, Sasha Levin wrote:
> >> Hi all,
> >>
> >> I've started seeing the following warning while fuzzing inside a KVM guest with the latest -next:
> > ? ? ? ?It's not a realistic attack, fortunately, since you need root
> > to get past open_exec() on any of those... ?Wait. ?How _did_ you get
> > past open_exec(), anyway? ?MAY_EXEC is not supposed to be granted on
> > anything that has no exec bits at all and AFAICS none of those files
> > have them.
>
> You could chmod +x and run them, no?

Can't. proc_setattr() will give you -EPERM and refuse to do anything
if you call it with ATTR_MODE in ->ia_valid.