Messages in this thread | | | From | Ming Lei <> | Date | Fri, 31 Mar 2017 16:21:40 +0800 | Subject | Re: [PATCH 1/8] Guard bvec iteration logic |
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On Thu, Mar 30, 2017 at 9:49 PM, Dmitry Monakhov <dmonakhov@openvz.org> wrote: > If some one try to attempt advance bvec beyond it's size we simply > dump WARN_ONCE and continue to iterate beyond bvec array boundaries. > This simply means that we endup dereferencing/corrupting random memory > region. > > Code was added long time ago here 4550dd6c, luckily no one hit it > in real life :) > > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> > --- > include/linux/bvec.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/include/linux/bvec.h b/include/linux/bvec.h > index 89b65b8..86b914f 100644 > --- a/include/linux/bvec.h > +++ b/include/linux/bvec.h > @@ -70,8 +70,7 @@ static inline void bvec_iter_advance(const struct bio_vec *bv, > struct bvec_iter *iter, > unsigned bytes) > { > - WARN_ONCE(bytes > iter->bi_size, > - "Attempted to advance past end of bvec iter\n"); > + BUG_ON(bytes > iter->bi_size);
This may not a good idea, especially Linus did not like BUG_ON(), please see the following link:
https://lkml.org/lkml/2016/10/4/1
Thanks, Ming Lei
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